Latest posts

REPRODUCTIVE SYSTEM

from Femosky110 on 06/11/2020 12:48 PM

Mammalian Reproductive System
Most mammal reproductive systems are alike; however, there are a few prominent differences between the "normal" mammal and humans. For example, the majorities of mammalian males have a penis which is stored internally until erect, and a few have a penis bone or baculum.

 

Furthermore, males of the majority species do not remain continually sexually fertile as humans do.

Like humans, the majority of mamalian groups have descended testicles located inside the scrotum, on the other hand, others have goes down testicles that relax on the ventral body wall, and other groups of mammals, like elephants, have undescended testicles are located deep within their body cavities close to their kidneys.

General Functions of the Female Reproductive System
The female primary reproductive organs are the ovaries. The functions of the ovaries include the production of female sex hormones and oocytes as well as secretions by glands in the reproductive system.

The accessory ducts include the uterine tubes, where fertilization takes place; the uterus, where the embryo grows; and the vagina, which serves as a birth canal and receives the penis during sexual intercourse.

In amniotes, fertilization is normally internal, with sperm transfer irregularly assisted by a male intromittent organ. In placental mammals, the reproductive structures have become well developed and specialized to make the act of giving birth possible.

Methods of Reproduction in Mammals
The three types of mammals differ in their methods of reproduction.

• Placental Mammals such as the cat are viviparous. Viviparity, or birth of live young, has separately evolved more than one hundred times in vertebrates. Nevertheless, a lot of vertebrates retain the shelled egg laying method of giving birth as a result of the nutrients made available by the shell and passed to the embyo.

• Monotremes are the most primitive types of mammals. They have maintained the reptilian oviparous method of reproduction and lay shelled eggs.

• Marsupials go through a fuzzy type of viviparity. They give birth to underdeveloped live young. When the young are born, they move to the permanent brood pouch, or marsupium. Development of the young is finished in the pouch.

Female Reproductive Structures In Mammals That Allow Viviparity
Ovary: The ovary is paired, almond-shaped organs that are propped up by the mesovarium, a part of the broad ligament. The ovary is the place of oogenesis and hormone production.

Oviducts: The oviducts are as well regarded as the uterine tubes. They receive the oocyte and make available a site for fertilization.

Infundabulum: This is the sideways part of the oviduct that lokes an open funnel. This feature is covered with ciliated and finger-like projections known as fimbrae which wrap over the ovary. The movements of the fimbrae brush the oocyte into the tube.

Ostium Tubae: The infundabulum unlocks medially through the ostium tubae.

Uterus: The oviducts come together into the bigger uterine horn. The two uterine horns mingle to form the uterine body. The entire structure is Y-shaped.

The mammalian uterus has developed a highly vascularized lining whose function is to receive, retain, and nourish a fertilized egg all through pregnancy.

During the pregnancy, the uterine horns block up the abdominal cavity. The other organs are pressed in all directions to give room to the developing fetus.

Vagina: The vagina is a thin-walled tube that is located posterior to the uterus. It makes a tube for the delivery of an offspring.

Evolution of a Secondary Sexual Characteristic
Mammary glands are unique to living mammals. They are formed from specific skin glands. Mammary glands play a role in lactating females when they produce milk for the nourishment of an offspring.

Female mammals are born with all the follicles they're ever going to have, and every one of the follicles possesses a primary oocyte. There are significant numbers of these. In humans the total number of primordial follicles present at birth can be up to 500,000 or more.

They are normally dormant until the stage of puberty. Hormonal changes that take place in the body at this stage will cause the eggs to get up from their dormant state. However, just a few among those thousands of egg would mature to the stage of ovulation.

Human beings possess a much longer reproductive life than the majority of other mammals, but even at that if a woman ovulates once every month from the ages of 12 to 50, she can only produce about 400-500 matured eggs that capable of being fertilized. That is one tenth of one percent of her total follicles.

Human Reproductive System
The human reproductive system is normally composed of internal fertilization through the process of sexual intercourse. During this process, the erect penis of the male is inserted into the female's vagina until the male ejaculates semen, which is composed of sperm, into the female's vagina.

The sperm afterwards travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the egg.

Upon successful fertilization and implantation, gestation of the fetus then occurs inside the female's uterus for just about nine months, this process is referred to as pregnancy in humans. The process of gestation comes to an end with birth. The process of giving birth is referred to as labor.

Labor results as a result of the contraction of the muscles of the uterus, the dilation of the cervix and the passage of the baby through the vagina which is the woman's reproductive organ.

Human's babies and children are almost defenseless and need and require high levels of parental care for lots of years. One major crucial type of parental care is to make use of the mammary gland to nurse the baby.

The female reproductive system has two-fold functions: To produce egg and to protect and look after the offspring until birth. The male reproductive system has one function, which is to produce and to dump sperm.

Humans have a lofty level of sexual differentiation added to the variations in roughly every reproductive organ, a lot of variation normally take place in the humans during the development of the secondary sexual characteristics.

Male Reproductive System
biology
The male reproductive system is composed of organs situated outside of the body and around the pelvis region of a male which plays a role in the reproduction process. The major express function of the male reproductive system is to make available the male sperm for fertilization of the ovum.

The major reproductive organs of the male can be classified into three categories. The first category is sperm production and storage. Production of sperm occurs in the testes which are housed in the temperature regulating scrotum, immature sperm then journey to the epididymis for development and storage.

The second category is the ejaculatory fluid producing glands which are the the seminal vesicles, prostate glands, and the vas deferens. The last category is those employed during copulation, and deposition of the spermatozoa (sperm) within the male. They include the penis, urethra, vas deferens, and Cowper's gland.

The main secondary sexual characteristics of males include: larger, extra muscular stature, deep voice, facial and body hair, broad shoulders, and development of an adam's apple. A crucial sexual hormone of males is androgen, and especially testosterone.

The testes release a hormone that regulates the development of sperm. This hormone is as well responsible for the development of physical characteristics in men like facial hair and a deep voice.

Human Female Reproductive System
biology
The human female reproductive system is a succession of organs principally situated in the interior part of the body and just about the pelvic region of a female which plays a role in the reproductive process.

The human female reproductive system is composed of three major parts: the vagina, which leads from the vulva, the vaginal opening, to the uterus; the uterus, which holds the developing fetus; and the ovaries, which produce the female's ova.

The breasts are involved during the parenting stage of reproduction, but in the majority of classifications, they are not regarded as part of the female reproductive system.

The vagina opens up on the outside through the vulva, which as well contains the labia, clitoris and urethra; during intercourse this area is greased by mucus secreted by the Bartholin's glands.

The vagina is attached to the uterus via the cervix, while the uterus is attached to the ovaries through the fallopian tubes. Each one of the ovaries possesses hundreds of egg cells or ova (singular ovum).

Roughly every 28 days, the pituitary gland releases a hormone that stimulates some of the ova to enlarge and grow. One ovum is released and it passes through the fallopian tube into the uterus.

Hormones manufactured by the ovaries get the uterus ready to receive the ovum. The lining of the uterus, known as the endometrium, and unfertilized ova discharged every cycle via the process of menstruation. If the ovum is fertilized by sperm, it attaches to the endometrium and the fetus develops.

Production of Gametes: Spermatogenesis and Oogenesis
The production of gametes takes place inside the gonads via a process referred to as gametogenesis. Gametogenesis takes place when certain types of germ cells undergo a cell division known as meiosis to divide the standard diploid number of chromosome (n=46) into haploids cells which contains only 23 chromosomes.

In males, this process of gamete production is referred to as spermatogenesis and occurs only after puberty the seminiferous tubules of the testes. The immature spermatozoon or sperm are then sent to the epididymis where they gain a tail and motility.

Each of the original diploid germs cells or primary spermatocytes forms four functional gametes which is each forever young. The production and survival of sperms require a temperature that is lower than the normal core body temperature.

Since the scrotum, where the testis is present, is situated outside the body cavity, it provides a temperature about 3°C below normal body temperature.

In females, gametogenesis is known as oogenesis which takes place in the ovarian follicles of the ovaries. This process does not generate mature ovum until puberty.

As opposed to the situation in males, every one of the new diploid germ cells or primary oocytes will form only a single mature ovum, and three polar bodies which are not able to be fertilized.

It has long been understood that in females, different from what is obtained in males, every one of the primary acolytes ever found in a female will be created before birth, and that the final stages of ova production will then not start until puberty.

However, current scientific data has challenged that hypothesis. The fresh data shows that in at least a number of species of mammal oocytes carry on replenishing in females a long time after birth.

Examples of related human reproductive organs
Male organ          Female organ            Shared function
Cowper's gland   Bartholin's glands    Lubrication secretions
Penis                    Clitoris Erectile       tissue and sensation
Testes                    Ovary                       Gamete production
Prostate gland     Skene's gland         Ejaculatory fluid and sensation

ANIMAL NUTRITION

from Femosky110 on 06/11/2020 12:45 PM

Animal Nutrition
Nutrition is defined as the process by which an organism gets food which is utilized for the provision of energy and things for its life sustaining activities. It includes ways an organism gets its food and as well the processes by which the nutrients in the food are converted to simpler molecules for use by the body.

 

Holozoic Nutrition
Animals exhibit holozoic nutrition because they are not able to manufacture their own food. Holozoic animals are roughly divided into three categories in relation to their mode of feeding. These three categories of animals are Herbivores, Omnivores, and Carnivores.

Herbivores feed on grasses, carnivores feed on animal fresh and omnivore feed on both glasses and flesh.

Digestive System in Cockroach (Invertebrates)
Nutrition in cockroach is holozoic and it is an omnivore, feeding on various types of organic matter. It eats pieces of food and grinds them before digesting them. Thus a cockroach has mouth parts that are modified accordingly for chewing the food.

Structure of the Human Digestive System
The structure of the human digestive system is tailored to the omnivorous diet. The human digestive system is made up of an alimentary canal, which is roughly 8 metres long. The alimentary canal takes care of digestion, absorption and egestion.

Mouth Cavity
The Mouth cavity is the anterior opening of the digestive system through which food is ingested. It has a muscular tongue which bears the taste buds. The human mouth is made up of two rows of teeth - upper and lower.

Pharynx
The Pharynx is the part of the alimentary canal that is located after the mouth. It is a funnel-shaped air and food passage.

Stomach
The oesophagus opens into the stomach. The stomach is situated on the left side of the abdomen. It is a sac-like organ, which is linked to the oesophagus at the anterior by a cardiac sphincter and to the small intestine at the posterior end by a pyloric sphincter.

The stomach is a flexible organ with a wall made up of folds. These folds unfasten to give room for more food.

It serves as a temporary storage organ for the food for about 4 hours. It is made up of three layers of muscles, not like the other parts of the alimentary canal, which assist in churning the food.

Small Intestine
Duodenum is a short part of the small intestine which is made up of loops and measures about 25 cm.

Large Intestine
The small intestine enlarges a little to form a tubular large intestine which is 5cm wide and 2m long.

Digestive Glands and Their Secretions
It is the largest gland and is found in the upper part of the abdomen on the right side just below the diaphragm. Its secretion is called bile juice. It is alkaline and rich in organic (steroid) salts called the bile salts.

The alkaline nature serves to neutralize the acidic pH of the gastric juice and creates the right environment for the intestinal enzymes to function.

Organ System: Gall Bladdar
This is a minute sac-like elongated organ close to the liver. The surplus bile secretion is stored in the gall bladder. It is linked with the liver by a duct known as the cystic duct. If there is no food in the intestine, the bile juice passes into the gall bladder and is stored there.

It is pumped out by the muscular contraction of the gall bladder wall when the food enters into the small intestine. The cystic duct empties into the widespread bile duct which opens into the small intestine.

Physiology of pancreas
The pancreas is located at the bend of the duodenum. It secretes pancreatic juice which possesses just about neutral pH (6 to 7). This juice is secreted into the common bile duct and subsequently into the duodenum. About 700cc of pancreatic juice is secreted daily.

Mechanism of Digestion
Renin is seen only in young children. The enzyme digests the milk protein, casein. Casein is hydrolysed into paracasein which in turn is precipitated as insoluble calcium paracaseinate. This is known as coagulation.

Renin secreted by the gastric mucosa of the calf is collected to manufacture rennet tablets used commercially to curdle milk.

Digestion Mechanism in Human
The bolus is then transported into the pharynx by an involuntary swallowing action. It is made simpler through the presence of mucus along the walls of the alimentary canal.

Hormonal Control of Digestion
Digestion is in fact carried out by enzymes but the secretion of these enzymes is regulated by the nervous system and the endocrine system.

Absorption
Digestion is as well regulated by the secretion of organic materials known as hormones by the endocrine glands. Every hormone has a particular target organ. The hormones get to the target organ via the blood stream. The hormones controlling digestion are secreted by the walls of the stomach and duodenum.

Assimilation
After the ingested food has been converted into a soluble form, the intestinal walls of ileum suck up the nutrients as well as water. Due to its larger surface area, skeletal wall lining the cavity and huge number of finger-like projections, known as the villi, the highest absorption occur in this part of the alimentary canal.

The absorbed food passes through the epithelial cells of the villi and then into the blood capillaries in the villi. From the capillaries, the fat-soluble substances move into the lymph. These materials are subsequently transported all through the body by the lymphatic system, which drains them into the blood near the heart.

The food that is digested is absorbed into the blood and lymphatic systems. The lymphatic system transports the digested fats as fatty acids and glycerol into the blood vessel going into the heart. The digested food in the blood stream reaches the liver.

In the liver excess glucose is stored as glycogen to be utilized when needed. The cells obtain the glucose they require from the blood directly for respiration. Cholesterol is produced from a few fatty acids.

The amino acids are utilized to form needed proteins. Excess amino acids are deaminated. During the process of deamination, ammonia is liberated as waste.

This ammonia is broken down into the less unsafe material known as the urea. The urea is subsequently transported through the blood stream to the kidney from where it is given out as urine.

Classification of foods
1. Carbohydrates
Carbohydrates are the main energy providers of the organism. They are composed of carbon, hydrogen and oxygen.

2. Proteins
Classification and Function of Proteins
Proteins are the main body builders of the body. They are compound molecules made up of carbon, hydrogen, oxygen and nitrogen and occasionally sulphur and phosphorus.

Proteins are used in the synthesis of enzymes (like pepsin, trypsin), hormones (like insulin, adrenaline), carrier proteins (like Haemoglobin), contractile proteins (like myosin, actin), structural proteins (like collagen) and defensive proteins or antibodies.

They as well produce skin pigments such as melanin and nucleic acids of the genetic material, DNA and RNA - purines and pyrimidines.

Fats
Fats are the major energy storers of the body. When fat is oxidized, they produce about two and a half times the energy of glucose or glycogen. This is why it majorly appropriate for energy storage.

Fat on the other hands makes use of more oxygen molecules for the oxidation process in comparison with carbohydrates which uses up less oxygen.

Fats are stored in adipose tissue in definite parts of the body like under the skin and between internal organs. As well as serving as an organ for storage, fats are also utilized to manufacture structural lipids like those of membranes.

Vitamins
Vitamins are a multifaceted group of organic compounds that are needed in small quantities for the control of different activities of the body. Although they are required in minute quantities, they are necessary for our well being.

The fact that the majority of them cannot be synthesized in the body, they ought to form a part of our diet. Deficiencies of these vitamins in the diet lead to deficiency disorders.

Minerals of Human Body
Minerals are inorganic nutrients which can be metallic and non-metallic elements that absorbed by the body in the form of salts. There are 24 elements that are utilized in our body. They possess many functions like tissue formation eg., the bone, conduction of nervous impulses, formation of RBCs, and so on.

There are eight key elements needed by man and the others are required in traces. The major elements are sodium, chlorine, potassium, calcium, phosphorus, sulphur and magnesium.

Some of the trace elements or microelements are fluorine, zinc, copper, iodine, iron, manganese, chromium, cobalt, and so on. Nevertheless all of them are crucial for the well-being of the human body. All the minerals are primarily obtained from the plants which absorb them from the soil.

Adult Balanced Nutrition
The human body needs different types of nutrients in order to keep the body healthy and fit. These nutrients ought to be taken properly in our diet. The diet that we follow ought to be balanced. Balanced diet is a diet, which contains all the nutrients required by the body in the right proportions.

Nutritional Deficiency Disorders
Nutritional disorders take place due to malnutrition. Malnutrition refers to bad nutrition and can as a result be applied to both undernourishment and overeating.

Undernourishment is a grave issue especially in the developing countries which occasionally have a large population percentage being deprived of a balanced diet or even a day of full meal. The majority of those affected are children who are below the age of five.

Undernourishment may as a result of proteins, vitamins or minerals deficiency. Deficiency of these nutrients results to diseases, time and again grave and lethal.

Vitamin Deficiency Diseases
The vitamin deficiency disease is caused by the deficiency of vitamin A, which affects the rod cells of the retina. This results to poor adaptation of eyes to dim or night light- a condition known as night blindness.

The cornea and the conjunctiva as well turn dry. This condition is known as xerophthalmia or dry eyes. Serious deficiency results in keratomalacia. In this case, ulcers develop on cornea, giving rise to eventual blindness.

Mineral Salt Deficiency Diseases
Mineral salt deficiency diseases are caused by deficiency of iron. Iron is essential for the production of haemoglobin, a protein that is an oxygen carrier in the blood.

When the level of haemoglobin in the blood drops, it results in the person feeling tired easily, loss of appetite, loss of weight and pale appearance as a result of oxygen lost in the blood.

This condition is referred to as anaemia. This condition can be averted and cured by eating food that are rich in iron like spinach, liver, milk, apple, guava, etc.

Digestive Systems
biology
Animals make use of the organs of their digestive systems to extract crucial nutrients from food they consume, which can later be assimilated.

Digestive Systems of Invertebrate
Invertebrate digestive systems are composed of a gastrovascular cavity with a single opening or an alimentary canal with a true mouth and anus.

Vertebrate Digestive Systems
Vertebrates may have one stomach, complex stomach chambers, or complementary organs that assist to break down ingested food.

Digestive System: Mouth and Stomach
Animal digestion starts in the mouth and subsequently transferred to the pharynx, into the esophagus, and after that into the stomach and small intestine.

biology
Digestive System: Small and Large Intestines
Nutrients are absorbed in the small intestine and waste is geared up for elimination in the large intestine.

Nutrition and Energy Production
Food Requirements
Essential nutrients are nutrients that cannot be manufactured by an animal's metabolism and need to be obtained from the diet.

Food Energy and ATP

ANATOMY AND SENSE ORGAN

from Femosky110 on 06/11/2020 12:42 PM

Anatomy and Structure of Human Sense Organs
The human sense organs are classified into 5: the organ of sight, organ of smell, organ of taste, organ of touch and organ of hearing. Each of the 5 senses is made up of an organ that has specific cellular structures that have receptors for specific stimuli.

 

These cells have links to the nervous system and therefore to the brain. Sensing is done at primordial levels in the cells and incorporated into sensations in the nervous system.

Sight is in all probability the main developed sense organ in humans, followed narrowly by organ of hearing.

biology
The Sense Organ of Sight
The eye is the organ of vision. It has a composite structure made up of a transparent lens that focuses light on the retina. The retina is enclosed with two essential types of light-sensitive cells-rods and cones.

The cone cells are sensitive to color and are situated in the part of the retina known as the fovea, where the light is focused by the lens. The rod cells on the other hand are not sensitive to color, but possess greater sensitivity to light than the cone cells.

These cells are found around the fovea and are in charge of peripheral vision and night vision. The eye is joined to the brain through the optic nerve. The point of this connection is known as the "blind spot" due to the fact that it is insensitive to light.

The brain joins the input of our two eyes into a distinct three-dimensional image. Again, even though the image on the retina is upturned due to the focusing action of the lens, the brain recompenses and provides the upright-side image perception.

Experiments have been conducted with subjects built-in with prisms that invert the images. The subjects pass through a preliminary period of immense confusion, but afterward they identify the images as upright.

The range of perception of the eye is extraordinary. In the dark, a substance formed by the rod cells increases the sensitivity of the eye so that it is possible to sense extremely dim light. In well-built light, the iris contracts minimizing the size of the aperture that admits light into the eye and a defensive ambiguous substance minimizes the exposure of the light-sensitive cells.

The range of light to which the eye is sensitive differs from the red to the violet. Lesser electromagnetic frequencies in the infrared are detected as heat, but cannot be seen. Elevated frequencies in the ultraviolet and beyond cannot be seen either, but can be detected as tingling of the skin or eyes depending on the frequency.

The human eye is not sensitive to the polarization of light- light that move back and forth on a definite plane.

Bees, on the contrary are sensitive to polarized light, and possess an image range that expands into the ultraviolet.

A few types of snakes possess specific infrared sensors that allow them to hunt in complete darkness merely with the help of the heat given out by their prey.

Birds possess an advanced concentration of light-sensing cells than humans have in their retinas, and as a result, have a more advanced visual acuity.

Color blindness or "Daltonism" is a widespread anomaly in human vision that makes it impractical to distinguish colors correctly. One type of color blindness results in the incapability of differentiating red from green.

This can be actual handicap for definite types of occupations. To a colorblind individual, a person with standard color vision would seem to possess an extrasensory perception.

Nevertheless, we want to put to one side the term "extrasensory perception" for perception that is ahead of the range of the normal.

biology
The Organ of Hearing
The ear is the sense organ of hearing. The outer ear sticks out away from the head and is shaped like a cup to guide sounds in the direction of the tympanic membrane, which transmits vibrations to the inner ear via a series of small bones in the middle ear known as the malleus, incus and stapes.

The inner ear, or cochlea, is a spiral-shaped cavity enclosed within by nerve fibers that respond to the vibrations and transfer impulses to the brain through the auditory nerve.

The brain joins the input of our two ears to establish the direction and distance of sounds.

The inner ear possess a vestibular system produced by three semicircular canals that are roughly at right angles to each other and which are answerable for the sense of balance and spatial direction.

The inner ear possess chambers overflowing with a viscous fluid and small particles (otoliths) consisting calcium carbonate. The association of these particles over tiny hair cells in the inner ear transmits signals to the brain that are interpreted as movement and speeding up.

The human ear can pick out frequencies from 16 cycles per second, which is an extremely deep bass, to 28,000 cycles per second, which is a very high pitch. Bats and dolphins can detect frequencies above 100,000 cycles per second.

The human ear can sense pitch alterations as minute as 3 hundredths of one percent of the original frequency in a few frequency ranges. A few individuals possess "perfect pitch", which is the capability to chart a tone accurately on the musical scale without indication to an exterior standard.

It is projected that less than one in ten thousand people possess perfect pitch, but speakers of tonal languages such as Vietnamese and Mandarin exhibits amazingly clear-cut absolute pitch in reading out collection of words due to the fact that pitch is a crucial aspect of passing on the meaning of words in tone languages.

The Organ of Taste
The receptors for taste, known as the taste buds, are located mainly in the tongue, but they are as well situated in the roof of the mouth and close to the pharynx. They are capable of detecting four basic tastes: salty, sweet, bitter, and sour.

The tongue as well can detect a sensation known as "umami" from taste receptors responsive to amino acids. By and large, the taste buds located near the tip of the tongue are sensitive to sweet tastes, while those in the backside of the tongue are sensitive to bitter tastes.

The taste buds on apex and on the side of the tongue are sensitive to salty and sour tastes. At the bottom of every taste bud there is a nerve that transmits the sensations to the brain.

The sense of taste works in coordination with the sense of smell. The number of taste buds differs considerably from person to person, but higher numbers add to sensitivity. Women, commonly possess a higher number of taste buds than men. As in the case of color blindness, a number of people are numb to a few tastes.

The Sense of Smell:
The nose is the organ in charge of the sense of smell. The cavity of the nose is covered with mucous membranes that possess smell receptors linked to the olfactory nerve. The smells themselves are composed of vapors of different substances.

The smell receptors interrelate with the molecules of these vapors and send out the sensations to the brain.

The nose as well has a structure known as the vomeronasal organ whose function has not been discovered, but which is suspected to be sensitive to pheromones that manipulate the reproductive cycle. The smell receptors are responsive to seven types of sensations that can be described as camphor, musk, flower, mint, ether, acrid, or putrid.

The sense of smell is sometimes momentarily lost when a person has caught a cold. Dogs possess a sense of smell that is a lot of times additionally sensitive than man's.

biology
The Sense of Touch
The sense of touch is dispersed all through the body. Nerve endings in the skin and other parts of the body send out sensations to the brain. A few parts of the body possess a larger number of nerve endings and, consequently, are more sensitive.

Four kinds of touch sensations can be recognized: cold, heat, contact, and pain. Hairs on the skin magnify the sensitivity and act as an early warning system for the body.

The fingertips and the sexual organs have the greatest concentration of nerve endings. The sexual organs have "erogenous zones" that when stimulated start a series of endocrine reactions and motor responses resulting in orgasm.

Away from the five sense organs
Apart from the 5 generally accepted and recognized sense organs of sight, smell, taste, touch, and hearing, human beings as well possess sense of consciousness of balance known as equilibrioception, pressure, temperature also known as thermoception sense of pain as well known as nociception, and motion all of which might involve the coordinated use of several sensory organs.

The sense of balance is regulated by a complex communication of visual inputs, the proprioceptive sensors which are controlled by gravity and stretch sensors located in the muscles, skin, and joints, the inner ear vestibular system, and the central nervous system.

Disturbances occurring in any part of the balance system, or even within the brain's integration of inputs, can cause the feeling of dizziness or unsteadiness.

Kinesthesia
Kinesthesia is the accurate responsiveness of muscle and joint action which permits us to coordinate our muscles when we walk, talk, and make use of our hands.

It is the sense of kinesthesia that allows us to touch the tip of our nose with our eyes shut or to become aware of which part of the body we need to scratch when we are experiencing itching.

Synesthesia
A few individual experiences a phenomenon known as synesthesia in which a single type of stimulus leads to the sensation of another. For instance, the hearing of a sound may lead to the sensation of the visualization of a color, or a shape may be sensed as a smell.

Synesthesia is hereditary and it is likely to take place or exist in 1 out of 1000 people with variations of form and intensity. The most widespread forms of synesthesia connect numbers or letters with colors.

Path of Sensory Impulses
The following is the part a sensory impulse takes before they are finally translated to the individual. The impulse from the receptors are transmitted through the nerve to the brain which translates it and send back the message through nerves to the effectors which would now react or respond accordingly.

Receptors > Nerves > Brain > Nerves > Effectors (such as muscles)> response

As illustrated above, our sensory organs first receives the stimuli transmits the nervous impulse to the brain which interprets it and take decision of what would be the best thing to do. The brain would then send the nerve impulses to the associated effectors or effectors muscle which would then respond accordingly.

A table illustrating he five human sense organs and their related sensory organs and stimuli

Action Senses Sensory Organs Stimulus
Eating Sense of Taste Tongue Taste
Listening Sense of Hearing Ear Light
Looking Sense of Sight Eyes Light
Touching Sense of Touch Skin Touch
Smelling Sense of Smell Nose Smell

CENTRAL NERVOUS SYSTEM

from Femosky110 on 06/11/2020 12:41 PM

Nervous Co-ordination and the Central Nervous System
The nervous system is composed of two major categories or types of cells: the neurons and glial cells.

 

Neurons
The nervous system is composed of a specific types of cell known as the neuron ("neurone" or "nerve cell"). The nervous system of all animals is made up of extremely specialised cells known as neurons which can detect, receive and transfer various kinds of stimuli.

Neurons are different from other cells in many ways, but their major basic function is that they interact with other cells through synapses, which are membrane-to-membrane junctions that contain molecular mechanism that permits speedy transmission of signals, both electrical and chemical.

Numerous types of neuron have an axon, a protoplasmic projection that can expand to far-away parts of the body and make thousands of synaptic contacts. Axons regularly move through the body in bundles known as nerves.

Even in the nervous system of a single species like humans, hundreds of various types of neurons are present, with a broad variety of morphologies and roles.

These consist of sensory neurons that transform physical stimuli like light and sound into neural signals, and motor neurons that transform neural signals into activation of muscles or glands; conversely in a lot of species the great majority of neurons obtain all their contribution from other neurons and transfer their output to other neurons.

Glial cells
Glial cells are non-neuronal cells that offer support and nutrition, sustain homeostasis, form myelin, and take part in the transmission of signal in the nervous system. In the human brain, it is projected that the total number of glia approximately equals the number of neurons, even though the proportions differ in various portions of the brain.

Among the majorly crucial role played by glial cells are to support neurons and clutch them in place; to provide nutrients to neurons; to electrically insulate neurons; to annihilate pathogens and get rid of dead neurons; and to make available guidance cues directing the axons of neurons to their targets.

A very crucial type of glial cell oligodendrocytesin the central nervous system and Schwann cells in the peripheral nervous system produces layers of a fatty substance known as myelin that enfolds around axons and makes electrical insulation which permits them to put out action potentials much more hastily and competently.

biology
Diagram showing the major divisions of the vertebrate nervous system

The nervous system of vertebrates humans inclusive is divided into the central nervous system(CNS) and the peripheral nervous system (PNS).

The (CNS) is the main division, and is made up of the brain and the spinal cord. The spinal canal possesses the spinal cord, whereas the head caries the brain.

The CNS is cased and shielded by the meninges, a three-layered system of membranes which include a tough, fibrous outer layer known as the dura mater. The brain is as well covered by the skull, and the spinal cord by the vertebral column.

The peripheral nervous system (PNS) is a combined name for all the nervous system structures that do not fall within the CNS.

The large majority of the axon bundles known as nerves are well thought-out to fit into the PNS, even while the cell bodies of the neurons to which they fit in exist in the brain or spinal cord. The PNS is somatic and visceral parts.

The somatic part is composed of the nerves that innervate the skin, joints, and muscles. The cell bodies of somatic sensory neurons are situated in dorsal root ganglia of the spinal cord.

The visceral part, as well known as the autonomic nervous system, possesses neurons that permeate the internal organs, blood vessels, and glands. The autonomic nervous system itself is composed of two parts: the sympathetic nervous system and the parasympathetic nervous system.

A few scientists as well include sensory neurons whose cell bodies is situated in the periphery for senses such as sense of hearing as part of the PNS; while others nonetheless omit them.

The vertebrate nervous system can as well be divided into areas known as grey matter and white matter. Grey matter which is merely grey in conserved tissue, and is better regarded as pink or light brown in living tissue possesses a high quantity of cell bodies of neurons.

White matter is mainly made up of myelinated axons, and takes its color from the myelin. White matter consists of all the nerves, and the majority of the interior of the brain and spinal cord.

Grey matter is created in clusters of neurons in the brain and spinal cord, and in cortical layers that line the surfaces of the brain and the spinal cord.

There is an anatomical rule which states that a cluster of neurons in the brain or spinal cord is known as a nucleus, while a cluster of neurons in the periphery is known as a ganglion. There are, nevertheless, a few exceptions to this rule, remarkably including the part of the forebrain known as the basal ganglia.

The Human Nervous System:-
The human nervous system is divided into two parts:

(i) Central Nervous System (CNS)

(ii) Peripheral Nervous System (PNS)

The CNS is composed of the brain and the spinal cord and is the location for information processing and control. The PNS is composed of all the nerves of the body that are connected with the CNS – the brain and spinal cord. The nerve fibres of the PNS are divided into two:

(a) Afferent Fibres

(b) Efferent Fibres

The afferent nerve fibres transmit impulses from tissues/organs to the CNS and the efferent fibres transmit regulatory impulses from the CNS to the particular peripheral tissues/organs.

The PNS is classified into two:

The somatic nervous system and autonomic nervous system

The somatic nervous system conveys impulses from the CNS to skeletal muscles whereas the autonomic nervous system conveys impulses from the CNS to the involuntary organs and smooth muscles of the body. The autonomic nervous system is again classified into sympathetic nervous system and parasympathetic nervous system.

The neuron as structural and functional unit of nervous system
A neuron is a tiny structure made up of three main parts, specifically, cell body, dendrites and axon.

Cell Body: The cell body possesses the cytoplasm with characteristic cell organelles and definite granular bodies known as Nissl's granules.

Dendrites: Dendrites are short fibres that branch repetitively and protrude out of the cell body. It is as well made up of Nissl's granules and is known as dendrites. These fibres transmit impulses towards the cell body.

Axon: The axon is an enlongated fibre, which is subdivided repeatedly at the distal end. Every branch ends like a bulb-like structure known as synaptic knob which contain synaptic vesicles bearing chemicals refered to as neurotransmitters. The axons convey nerve impulses away from the cell body to a synapse or to a neuro-muscular junction.

In respect of the number of axon and dendrites, the neurons are separated into three types:

(a) Multipolar: A neuron that contains one axon and two or more dendrites; located in the cerebral cortex,

(b) Bipolar: A neuron that contains one axon and one dendrite, located in the retina of eye and

(c) Unipolar : A neuron with cell body and one axon only; usually visible in the embryonic stage).

biology
The axon is made up of two types, namely, myelinated and nonmyelinated axon. The myelinated nerve fibres are covered with Schwann cells, which develop into a myelin sheath about the axon.

The gaps connecting two adjacent myelin sheaths are known as nodes of Ranvier. Myelinated nerve fibres are located in the spinal and cranial nerves.

Unmyelinated nerve fibre is covered by a Schwann cell that does not develop into a myelin sheath about the axon, and is frequently created in autonomous and the somatic nervous systems.

The human central nervous system
biology
The brain is the central information processing organ of our body, and functions as the 'command and control system'.

It regulates the voluntary movements, balance of the body, performance of vital involuntary organs like the lungs, heart, kidneys, etc., thermoregulation, hunger and thirst, circadian (24-hour) rhythms of our body, actions of quite a lot of endocrine glands and human actions.

It is as well the site for processing of vision, hearing, speech, memory, intelligence, emotions and thoughts.

The human brain is well sheltered by the skull. Inside the skull, the brain is enveloped and shielded by cranial meninges made up of an outer layer called dura mater, a very thin middle layer known as arachnoid and an inner layer touches the brain tissue known as the pia mater. The brain can be classified into three major parts:

(i) The Forebrain,

(ii)The Midbrain, and

(iii) The Hindbrain

biology
Forebrain
The forebrain is made up of the cerebrum, thalamus and hypothalamus. Cerebrum consists of the greater part of the human brain. A profound cleft splits the cerebrum longitudinally into two halves. These two halves are known as the left and right cerebral hemispheres.

The hemispheres are linked by a tract of nerve fibres known as corpus callosum.

The layer of cells which envelops the cerebral hemisphere is known as the cerebral cortex and is made up of high up folds. The cerebral cortex is known as the grey matter as a result of its greyish appearance. The neuron cell bodies are intense here resulting to that colour.

The cerebral cortex is composed of motor areas, sensory areas and large regions that are not classified as sensory or motor in function. These regions are known as the association areas. They are responsible for intricate functions such as intersensory associations, memory and communication.

Fibres of the ducts are covered with the myelin sheath, which makes up the inner part of cerebral hemisphere. They offer an opaque white look to the layer and, therefore are known as the white matter.

The cerebrum wraps just about a structure known as thalamus, which is the main coordinating centre for sensory and motor signals. An additional highly essential part of the brain –the hypothalamus is found at the base of the thalamus.

The hypothalamus has some centres which regulate the body temperature, desire for eating and drinking. It as well possesses many groups of neurosecretory cells, which secrete hormonesknown as the hypothalamic hormones.

The Midbrain
The midbrain lies between the thalamus/hypothalamus of the forebrain and pons of the hindbrain. A canal known as the cerebral aqueduct passes via the midbrain. The dorsal part of the midbrain made up of mainly four round protrusions or lobes known as corpora quadrigemina. Midbrain and hindbrain together act as the stem of the brain.

Hindbrain
The hindbrain is made up of the pons, cerebellum and medulla which as well known as the medulla oblongata. Pons is made up of fibre ducts that can be integrated to different parts of the brain.

Cerebellum has extremely complicated surface which enable it to provide the extra space needed for a lot of neurons. The medulla of the brain is linked to the spinal cord. The medulla contains centres which control respiration, cardiovascular reflexes and gastric secretions.

BIOLOGY: HORMONAL COORDINATION

from Femosky110 on 06/11/2020 12:09 PM

Hormonal coordination
All animals are made up of chemical components formed by exocrine or endocrine glands. Exocrine glands discharge their chemicals into ducts. The endocrine glands discharge their secretions, the hormones, openly into the blood-stream.

 

These hormones are afterward carried to other parts of the body known as target organs, where in very minute quantities, they bring out cellular responses.

Hormones are specifically-acting organic compounds with changeable chemical compositions, frequently steroids, proteins, peptides or amino acids. Based on their common roles, hormones are metabolic.

They either stimulate or retard metabolic activities. They are trophic-they regulate rate and secretion of other endocrine glands and morphogenetic –they influence rate and development of assorted parts.

Hormones are an additional means of coordination and communication. Together with the nervous system, the endocrine system forms a combined neuro-endocrine system. The hormone pathway is by the blood stream, while nervous pathway is by the neuron-reflex arc.

Glands are classified into two:
• Exocrine glands

• Endocrine glands

biology
The diagram of Exocrine and Endocrine Gland Showing Release of Secretion

Exocrine glands are those glands which pour their secretions into a duct. For instance, sweat glands, tear glands, and so on.

Endocrine glands are those glands which are abundantly filled with blood vessels and discharge their secretions directly into the blood vessels. The secretions get to their target through blood. These glands are known as the ductless glands as they do not possess ducts. Examples of ductless glands are: thyroid, adrenal, etc.

The control and coordination of the various bodily functions is as well done with the assistance of the endocrine system. The endocrine system exerts chemical power over the activities. These chemicals are secreted from organs known as endocrine glands.

The secretions of the endocrine glands are known as hormones. Hormones possess the following characteristics:

• they may be proteinaceous or non-proteinaceous -amino acids or steroids

• they are secreted as per requirement and not stored, only excreted

• their secretion may be controlled by nerves or by feedback effect

• they are transported through the blood

• they mainly give rise to long-term effects like growth, alteration in behaviour, etc.

• they do not catalyze or speed up any reactions

• they function by motivating or inhibiting the target organs.

Hormones can be defined as secretions that are discharged into blood in order to get to a particular target organ.

The human endocrine system is composed of the following glands:

• Hypothalamus

• Pineal

• Thyroid

• Parathyroid

• Pituitary

• Thymus

• Adrenal

• Pancreas

• Ovary in female

• Testes in male

biology
Position of Various Endocrine glands in the Human Body
Pituitary Gland
The pituitary gland also known as hypophysis is about the size of a large pea, situated beneath the brain, at the back the nasal cavity on the floor of the cranium. It is affixed by a stalk to the hypothalamus part of the brain on the undersurface of the cerebrum.

It is positioned in the sphenoid bone of the skull and is strictly invested by a connective tissue capsule.

biology
The location of Pituitary gland
The pituitary gland is referred to as the master endocrine gland due to its control over quite a few other endocrine glands.

Nevertheless, the body's actual master gland is the hypothalamus of the brain which takes charge of the secretions of the anterior pituitary by discharging and inhibiting hormones. Also, the pituitary itself is as well regulated by feedback from other glands.

The anterior lobe of the pituitary gland manufactures six dissimilar hormones. Among them, two function directly on body tissue (somatotrophic) and the other four controls the action of other endocrine organs.

The middle lobe known as pars intermedia discharges only one hormone known as intermedin. This hormone is in charge of the control of skin colors in lower vertebrates, but is vestigial in mammals, and has no function in humans.

The posterior lobe purpose is for storage and discharge point for two hormones secreted by the hypothalamus-neurosecretory cells and carried to the lobe via a linking duct referred to as the neurohypophysis).

The hormones of the Pituitary gland
The anterior lobe of the pituitary gland secretes six hormones. They are:

1. Thyroid stimulating hormone (TSH) or thyrotropin:
This hormone stimulates the secretion of thyroxin from the thyroid glands.

2. Somototropic or growth hormone:
This hormone controls growth of tissue, bone, muscles and internal organs, and as well influences metabolic processes. Hyper secretion in early on of life gives rise to a condition known as gigantism, and after the growth period in adult life it leads to acromegaly.

In acromegaly, excess secretion becomes visible after long bones have become hardened and the growth continues alone in certain bones, leading to lengthening of forelimbs, hindlimbs, and enlarged jaw and face.

Hypo secretion during growth years leads to pituitary infantilism, a kind of dwarfism, in which an adult is not above three or four feet tall, and is typically sexually immature.

3. Follicle stimulating hormone (FSH):
The follicle stimulating hormone excites the ovaries and testes. In females, it controls the development of grafian follicles or ova. In males, FSH influences spermatogenesis. That is the production of sperm by the seminiferous tubules of the testes.

4. Adrenocorticotropic hormone (ACTH):
This hormone motivates the adrenal cortex and controls the secretion from the adrenal glands.

5. Luteinizing hormone (LH) along with FSH:
This hormone in addition to FSH is responsible for the growth of ovarian follicles, release of mature ova or egg, development of the corpus luteum, production of progesterone and regulation of menstrual cycle in females. In males, LH stirs the testes to secrete testosterone or ICSH- interestitial cell stimulating hormone.

6. Prolactin kicks off the secretion of milk by the mammary glands after the birth of a baby. In the nonexistence of prolactin, milk secretion is put to a stop.

biology
Relationship between the pituitary and other endocrine glands

(---------In charge of feed back or inhibition)

(---------Pituitary Hormones that stimulate other glands)

The intermediate lobe of the pituitary gland:
The intermediate lobe secretes only one hormone, Melanophore Stimulating Hormone (MSH), or intermedin, which regulates the pigmentation of the skin in varieties of vertebrates. It darkens the color of the skin. Nevertheless it is of no significant purpose in humans.

The posterior lobe of the pituitary gland

The posterior lobe secretes the following hormones:

1. Oxytocin: This hormone is responsible for the contraction of the uterus in females during childbirth and also controls lactation or the release of milk.

2. Antidiuretic hormone (ADH) or Vasopressin: This hormone stimulates the kidneys to reabsorb more water, preventing too much water loss by urination. Chronic deficiency of ADH causes diabetes insipidus (polyuria), in which the patient feels extremely thirsty and passes a large amount of dilute urine.

The Thyroid Gland
biology
Position and Structure of thyroid gland:
All vertebrates have a pair of thyroid glands, situated in the neck just beneath the larynx or Adams apple. In human being, the thyroid gland is made up of two lobes-H-shaped that is positioned on either side of the trachea.

The two lobes are linked by a narrow isthmus that passes in front of the trachea. The gland differs in size with the variation in sexual development, diet and age.

The histology of the thyroid gland:
The thyroid gland is made up of a large number of round or oval follicles enclosed by connective tissue with a large number of blood vessels. Every one of the follicle is lined by one-cell thickcuboidal epithelial cells.

The cavities of the follicles are packed with viscous protein material known as colloid. The thyroid hormone, thyroxine contains iodine atoms. It is not stored in the cells of the thyroid, but in the colloid enriching the follicles.

The function of thyroid cells is to pull iodine out of the blood. This is then integrated into the protein thyroglobulin, which is subsequently hydrolyzed into the energetic hormone thyroxine.

Transverse section through the thyroid gland
The hormones of the Thyroid Hormones
Thyroid glands manufacture a hormone known as thyroxine. The secretion of thyroxin is restricted by TSH which is manufactured in the the pituitary. The hypo secretion or under secretion of thyroxine in a child leads to a condition known as cretinism.

This condition exhibits itself by retarded growth and development (dwarfism), a overhanging abdomen, mental retardation, puffy skin and stumpy metabolic rate.

In adults hypo function results in myxedema; the symptoms are a low metabolic rate, reduction in mental and physical activity, and increase in weight, puffy skin, a decrease in heart beat and body temperature, and loss of hair.

When hypofunction or under secretion leads to a deficiency of iodine in diet, swelling of the thyroid which leads to a condition known as simple goiter.

In a bid to grab more iodine from the blood, the gland enlarges follicles and grows excessively. Hypofunction can be cured with a supply of iodized salt, sea food, and by surgery foods with the aim of getting rid of excess thyroid tissue.

In amphibians, thyroxine plays a vital role during metamorphosis. If thyroid function of an embryo or young tadpole is repressed for instance by removing the thyroid gland, then the animal remains a tadpole permanently.

On the contrary, if a young tadpole is offered an excess of thyroxin, the larva metamorphoses ahead of time into a miniature froglet.

Hyperfunction leads to a boost on the rate of metabolism of about 40%, abundant sweating, augmented food intake but loss of weight, high blood pressure, nervous tension and muscular weakness.

Some patients with hyperthyroidism possess protruding eyeballs, a condition known as exophthalmos. The swelling of thyroid gland as a result of hypersecretion gives rise to exophthalmic goiter.

Another hormone manufactured by the thyroid gland is calcitonin. It regulates the level of blood calcium. Calcitonin is discharged by the thyroid when there is an elevated level of calcium in the blood. The surplus Calcium is next reduced and dropped in bones.

To summarize all we have discussed:
• The chemicals controlling the majority systems of vertebrates are made up of secretory cells, which are structured into exocrine and endocrine glands. Endocrine glands function is to secrete hormone into the blood. A hormone is a biological molecule (chemical transmitter) which works on target organs and elicits a lot of cellular activities.

• The key endocrine organs are the hypothalamus, pituitary gland, thyroid gland, parathyroids, adrenal glands, islets of Langerhans, testis and ovary.

• The pituitary gland is referred to as the master endocrine gland. It is positioned beneath the brain, and posseses three divisions-the anterior lobe, middle lobe and posterior lobe.

• The anterior lobe secretes six hormones-the TSH, somatotrophic hormone, FSH, ACTH, LH and prolactin, whereas the posterior lobe secretes oxytocin and antidiuretic hormone (ADH). Middle lobe has no function in humans.

• The malfunctions of the pituitary cause various conditions like gigantism, acromegaly, pituitary infantilism, and diabetes insipidus and so on

• The thyroid gland is situated in the neck and is made up of thyroid follicles which contain colloid.

• The Thyroid gland secretes the hormone thyroxin; hypofunctin Hyperthyroidism leads to exophthalmos and exophthalmic goiter.

• The hormone calcitonin regulates the blood calcium level.

• The majority of biological or chemical control systems function on feed back

BIOLOGY: RESPIRATORY SYSTEM

from Femosky110 on 06/11/2020 12:07 PM

The Respiratory System and Gas Exchange
Cellular respiration is the breakdown of organic molecules to form ATP. Enough supply of oxygen is needed for the aerobic respiratory machinery of Kreb's Cycle and the Electron Transport System to effectively translate stored organic energy into energy rapt in ATP.

 

Carbon dioxide is as well manufactured through the metabolism of the cell and ought to be expelled from the cell. There ought to be an exchange of gases: carbon dioxide departing from the cell, oxygen entering the cell.

Animals possess organ systems concerned with the facilitation of this exchange in addition to the transport of gases to and from exchange areas.

Bodies and Respiration
Single-celled organisms substitute gases unswervingly across their cell membrane. Nevertheless, the slow rate of diffusion of oxygen as compared to carbon dioxide put a limit to the size of single-celled organisms.

All simple animals that do not possess specialized exchange surfaces possess flattened, tubular, or thin shaped body structures, which are the main effective one for exchange of gases. Nevertheless, these uncomplicated animals are quite small in size.

Large animals cannot preserve gas exchange by diffusion across their outer surface. They developed a selection of respiratory surfaces that all enlarge the surface area for exchange, thereby permitting giving room for broader bodies.

A respiratory surface is enveloped with thin, soggy epithelial cells that permit oxygen and carbon dioxide to be exchanged. Those gases can only pass through the cell membranes when they are melted in water or an aqueous solution; this means that all respiratory surfaces ought to be moist.

Methods of Respiration
Single-celled organisms exchange gases straightforwardly crosswise their cell membrane. Sponges and jellyfish for example do not have special organs for gas exchange and they obtain gases directly from the nearby water.

Flatworms and annelids make use of use their outer surfaces for gaseous exchange. Arthropods, annelids, and fish make use of gills; terrestrial vertebrates make use of internal lungs.

The Body Surface respiration known as cutaneous respiration
Flatworms and annelids make use of their outer surfaces for gaseous exchange. Earthworms possess a series of thin-walled blood vessels referred to as capillaries. Gas exchange takes place at capillaries located all through the body in addition to those in the respiratory surface.

Gills
Gills to a great extent increase the surface area for exchange of gases. They are present in a lot of animal groups in addition to the arthropods which includes a lot of some terrestrial crustaceans, annelids, fish, and amphibians.

Gills characteristically are complicated outgrowths enclosing blood vessels covered by a thin epithelial layer. In general, gills are organized into a series of plates and may be inside the body like in the crabs and fish or outside the body like in amphibians.

Gills are highly efficacious at eliminating oxygen from water: there is just 1/20 the quantity of oxygen available in water as in an identical volume of air. Water passes through the gills through one direction whereas blood passes in the opposite direction via gill capillaries. This countercurrent movement maximizes the transfer of oxygen.

Tracheal Systems
A lot of terrestrial animals posses their respiratory surfaces in the interior part of the body and linked to the outside by a group of tubes. Tracheae are these tubes that transmit air straightforwardly to cells for gas exchange.

Spiracles are apertures at the body surface that show the way to tracheae that branch into lesser tubes referred to as tracheoles. The tubes divide repetitively in order to let excessively fine tubules, tracheoles, get to the individual cells or undersized groups of cells inside the body.

The tracheae will not perform well in animals whose body is longer than 5 cm.

Lungs
Lungs are internal growths of the body wall that link to the exterior by a group of tubes and small openings.

Lung breathing was likely discovered and developed about 400 million years ago. Lungs are not only found in vertebrates, it is as well found in a few types of terrestrial snails possess gaseous exchange structures like those obtained in frogs.

Arthropods have open circulatory systems with an outstanding heart in receipt of blood from the hemocoel and pumping it into vessels for circulation to the body.

Depending on the sort of respiratory organ, the arthropod has, the circulatory system and may or may not be essential movement of oxygen to the body tissues. Those animals that do not necessarily need the blood for the circulation of respiratory gases like insects may not possess a respiratory pigment.

Respiration in invertebrate
Respiratory System Principles
1. The transportation of an oxygen-containing medium so it comes in contact with a moist membrane overlying blood vessels.

2. Diffusion of oxygen from the oxygen containing medium into the blood.

3. The transportation of oxygen to the tissues and cells of the body.

4. Diffusion of oxygen from the blood into the cells.

5. Carbon dioxide traces a path opposite to that of oxygen.

biology
The Human Respiratory System
The Pathway of the human respiratory system involve the following:

• Air is taken through the nostrils

• It then travels via the nasopharynx,

• To the oral pharynx

• via the glottis

• into the trachea and

• into the right and left bronchi, which divides and re-branches into

• bronchioles, each of which ends in a cluster of

• alveoli

It is just in the alveoli of the lung that the actual gas exchange occurs. There are a few 300 million alveoli in two adult lungs. These makes available a surface area of a few 160 m2 nearly equal to the singles area of a tennis court and 80 times the area of our skin!

Breathing
In mammals, the diaphragm splits the body cavity into the

• abdominal cavity, which possesses the viscera like the stomach and intestines and the

• thoracic cavity, which has the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse.

This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, re-inflation takes place as the air is slowly absorbed by the tissues.

Because of this bond, any act that increases the volume of the thoracic cavity makes the lungs to expand, making air to rush into them from the surrounding.

During the process of inspiration or inhalation,

The external intercostal muscles contract, raising the ribs up and out.

The diaphragm contracts, pulling it down.

During the process of expiration or inhalation, these processes are repeated and the normal elasticity of the lungs brings them back to their standard volume. At rest, we breathe in air 15–18 times every minute exchanging roughly 500 ml of air.

In more strenuous expiration,

The inside intercostal muscles pull the ribs down and inward

The wall of the abdomen contracts causing the stomach and liver to move upward.

Under these conditions, a standard adult male can flush his lungs with roughly 4 liters of air at every breath. This is known as the vital capacity. Even with greatest expiration, roughly 1200 ml of residual air remain.

Protozoan, porifera and coelenterate do their gaseous exchange oxygen and carbondioxide, through their body surface.

Platyhelminthes and nemahelminthes exhibit anaerobic respiration. Energy (ATP) is manufactured by glycolysis. Glycogen is further sub-divided into unstable fatty acid, CO 2 and energy. CO 2 is then expelled via body surface.

ANNELIDA: In annelid, respiratory organ is absent. Gaseous exchange occurs via the skin (cutaneous respiration), gills (branchial respiration), parapodia. Parapodium is extremely involved in (polychaetae) this process.

Every one of the parapodia possesses a capillary network and is highly supplied with blood. Body wall dorso-ventrally is made up of blood capillaries.

Haemocoelomic fluid blood gets their oxygen via the network. Respiratory pigment haemoglobin boosts the intake of oxygen by haemocoelomic fluid.

There is no specialized structure in Hirudinae and oligochaetae for exchange of gases but they do by cutaneous respiration.

Arthropoda
Aquatic arthropods characteristically possess gills for respiration apart from some exceptionally small species which have no special respiratory structures. Terrestrial arthropods make use of many different respiratory organs; the most exclusive one is the tracheal system.

There are two types of respiration in arthropods. They are Aquatic respiration and Aerial respiration.

Aquatic respiration: This type of respiration makes use of the dissolved oxygen. Aquatic respiration occurs in the following manner:

Gills are fragile feather-like development of the thoracic appendages like in the palaemon (prawn) and penaeus (scorpion), crab and tracheal gills are present in mayfly, damselfly and stonefly. Larvae have gills (blood gills and book gills) and crustacean via their body surface. Gills are extremely vascularised.

Aerial respiration: makes use of the oxygen from the air. This type of respiration is obtained in terrestrial arthropods. The respiratory organs are listed below:

a. Tracheal system ---- mainly found insects, centipedes , millipedes and a lot of arachnids.

b. Book lung ----- is found scorpion. (Extemely vascularised chamber)

c. simple lung ----- is found in terrestrial coconut crab

d. Air tube ----- This is found in terrestrial crustacean.

Summary of respiration in invertebrate
1. Express diffusion of gases to lung, gill and dermal papulae.

2. Absence of respiratory organ in lower ones but higher has composite structure for respiration

3. Express assimilation of o2 but in higher o2 rapt into coelomic fluid then transported to the assorted tissue.

4. Aquatic take dissolved o2 but higher ones either dissolved o2 or o2 expressively from air.

5. Those that possess single respiratory organ are higher than one respiratory organ

The adaptive significance of the variation in the structure of the respiratory organ of organisms living in terrestrial and those in aquatic environments

A surface that takes in oxygen ought to be kept moist. This is not an issue for aquatic organisms since they are covered with water. But terrestrial organisms would lose a huge amount of water to the dry air through the process of evaporation from the respiratory surfaces.

Therefore the majority of terrestrial animals possess their respiratory surfaces inside the body to reduce the loss of water by evaporation.

Hard exoskeleton system (arthropods) and scale in reptile are two good examples that illustrate this minimal loss of water.

BIOLOGY: HOMEOSTASIS

from Femosky110 on 06/11/2020 12:06 PM

Homeostasis
Homeostasis, which is as well spelt as homoeostasis or homœostasis is the property of a system in which variables are synchronized in order to let the internal conditions stay stable and comparatively constant.

 

Examples of homeostasis include the regulation of body temperature and the maintenance of the balance between acidity and alkalinity (pH). It is a process that maintains the constancy of the human body's internal environment in reply to changes in exterior conditions.

Every living organism maintains a balance between multifaceted set of interrelating metabolic chemical reactions. From the simplest unicellular organisms to the most composite plants and animals, interior processes function to maintain the conditions within fixed limits to permit these reactions to ensue.

Homeostatic processes act at all the five level of organization of life- the cell, the tissue, and the organ, in addition to the whole organism.

The major Homeostatic processes comprise the following:
1. Warm-blooded or endothermic animals for example mammals and birds sustain a steady body temperature, while ectodermic animals roughly every other organisms show evidence of broad body temperature variation.

The benefit of temperature regulation is that it permits an organism to function efficiently in a broad range of environmental conditions. For example, ectoderms have a propensity to turn sluggish at low temperatures, while an ectoderm that is with them at the same place tends to be completely active.

That thermal firmness arrives at a price, given that an automatic regulation system needs extra energy.

If the temperature increases, the body loses heat through sweating or gasping, through the latent heat of evaporation. If the temperature falls, it is offset by amplified metabolic action, by quivering, and in animals that have fur or feather by making thicker the coat.

2. Regulation of the pH of the blood at 7.365. pH is a measure of alkalinity and acidity of a medium and in this case the blood.

3. Another substance that is being regulated by animals is their blood glucose concentration. Mammals regulate their blood glucose with insulin and glucagon. The human body maintains constant glucose levels the majority of times during the day even after an individual observed a 24-hour fast.

Even during long periods of fasting, glucose levels are reduced only very to some extent.

Insulin, secreted by the beta cells of the pancreas, efficiently transports glucose to the cells of the body by initiating those cells to reserve more of the glucose for their own utilization.

If the glucose level inside the cells is high, the cells will convert it to the insoluble glycogen to thwart the soluble glucose from meddling with cellular metabolism. Eventually this lowers blood glucose levels, and insulin assists to avert hyperglycemia.

When insulin is lacking or cells become resistant to insulin, it leads to a condition known as diabetes occurs. Glucagon, secreted by the alpha cells of the pancreas, persuades cells to break down accumulated glycogen or convert non-carbohydrate carbon sources to glucose through the process known as gluconeogenesis, thereby averting hypoglycemia.

4. The kidneys are used to expel excess water and ions from the blood. These are afterward removed from the body in form of urine. The kidneys carry out a very important role in homeostatic regulation in mammals, expelling surplus water, salt, and urea from the blood.

5. If the water content of the blood and lymph fluid falls, it is reinstated at first by extracting water from the cells. The throat and mouth turn dry, so that the symptoms of thirst stimulate the animal to drink.

6. If the oxygen level of the blood falls, or the carbon-dioxide concentration rises, blood flow is boosted by further forceful heart action and the speed and depth of breathing as well rises.

7. Sleep timing depends on a balance between homeostatic sleep tendency, the requirement of sleep as a function of the quantity of time gone ever since the last sufficient sleep experience, and circadian rhythms that decide the perfect timing of a properly planned and curative sleep experience.

The homeostatic Control mechanisms
All homeostatic control mechanisms have a minimum of three mutually dependent constituents for the variable being regulated: The receptor is the sensing element that watches and reacts to changes in the environment.

When the receptor notices a stimulus, it gives out information to a "control center", the element that sets the range at which a variable is preserved. The control center establishes a suitable response to the stimulus.

The control center subsequently sends signals to an effector, which may be muscles, organs, or other body structures that collect signals from the control center.

After collecting the signal, a alteration is to made to annul the effect through the process of negative feedback mechanism.

Negative feedback mechanisms
Negative feedback mechanisms involve the reduction of the output or activity of any organ or system back to its standard level of functioning. A first-rate example of this is the regulation of blood pressure.

Blood vessels can detect resistance of blood flow over the walls when blood pressure rises. The blood vessels operate as the receptors and they convey this message to the brain.

The brain subsequently sends a message to the heart and blood vessels, both of which are the effectors. The heart rate would reduce as the blood vessels' diameter increases.

The process is known as vasodilation. This alteration would make the blood pressure to return to its standard level. The reverse would take place when blood pressure goes downs, and would lead to vasoconstriction.

Another significant instance is when the body is deprived of food. The body would at that point rearrange the metabolic set to a level that is less than regular value. This would permit the body to go on functioning, at a slower rate, although the body is suffering from starvation.

This is why people who are abstaining from intake of food as a means of weight loss would be able to lose some weight at the beginning but difficult as time goes on. This is because the body has readjusted itself to a lesser metabolic set-point to give the body the opportunity to live with its small energy supply.

Exercise can alter this effect by boosting the metabolic requirement.

Homeostatic imbalance
A lot of diseases involve a disturbance of homeostasis.

As the organism ages, the efficiency in its control systems becomes reduced. The inefficiencies slowly result in an unbalanced internal environment that boosts the risk of illness and results to the physical alterations connected with aging.

Certain homeostatic imbalances, like high central temperature, an elevated concentration of salt in the blood, or little concentration of oxygen, can produce homeostatic emotions like warmth, thirst, or breathlessness, which trigger off behavior meant to restore homeostasis like pulling off a sweater, drinking or slowing down.

All living organisms have perfect environmental conditions for survival and reproduction. Animals possess an interior environment together with the exterior environment they are residing in.

If their interior environment deviates too much from that ideal environmental conditions, they may witness reduction of function or they may even die. Homoeostasis is the custom-made ability of an organism to normalize its interior environment to handle and deal with alterations in the outside environment.

Animals are classified into two distinct categories with regards to the regulation of their internal environment or homeostasis. These two categories of animals are: conformers and regulators.

Conformers, or ectotherms, do not have the ability to maintain their internal environment when confronted with harsh and non conducive external environmental conditions.

For that reason, they are compelled to at all time look for favorable environmental conditions and exhibits behaviors intended to work against the environmental face up to. An example of a conformer is a lizard, which will lie around in the sun to add to its internal temperature or look for shade to reduce it.

The kidney and their functions
The human kidneys are two bean-shaped organs, each nearly the size of a fist. They are to be found just below the rib cage, one on either side of the spine. Every day, the two kidneys sort out approximately 120 to 150 quarts of blood to manufacture about 1 to 2 quarts of urine made up of wastes and additional fluid.

The urine passes from the kidneys to the bladder via two slender tubes of muscle known as ureters, one on either side of the bladder. The bladder stocks up urine.

The muscles of the bladder wall hang about relaxed while the bladder gets filled with urine. As the bladder fills to capacity, signals transferred to the brain signal the individual to set out to go to the toilet soon.

When the bladder is emptied, urine passes out of the body via a tube known as the urethra, to be found at the bottom of the bladder. In men the urethra is elongated, while in women it is small.

The diagram of human body showing the location of the urinary tract

biology
Why the kidneys are very essential in human body
The kidneys are very essential to the human body because they carry ut the functions of excretion and osmo-regulation. This means they function to ensure that the composition, or makeup, of the blood remains stable and unchangeable which allows the body function optimally.

The functions of the kidney are listed below:

To put a stop to the upsurge of wastes and additional fluid in the body

To maintain the levels of electrolytes like sodium, potassium, and phosphate and keep them stable.

To produce hormones that assist to:

standardize the blood pressure

produce the red blood cells

makes bones to remain rigid and strong

The mode of operation of the human Kidney
The kidney is not a single large filter. Each one of the kidneys is composed of roughly one million filtering units known as nephrons. Every one of the nephrons filters a little amount of blood. Each nephron contains a filter, known as the glomerulus, and a tubule.

The nephrons function through a two-step process. The glomerulus allows fluid and waste products to travel through it; but on the other hand, it inhibits the passage of blood cells and large molecules, mainly proteins through it.

The filtered fluid after that travels through the tubule which returns required minerals back to the bloodstream and eliminates wastes. The end product of the filtration results in what is known as urine.

biology
The structure of kidney nephron
In summary; Points to commit to memory

• Every day, the two kidneys sift nearly 120 to 150 quarts of blood to yield roughly 1 to 2 quarts of urine. The urine is made up of wastes and additional fluid.

• The kidneys are significant due to the fact that they maintain the composition, or makeup of the blood constant, which allows the body to function optimally.

• Each one among the two human kidneys is composed of roughly a million filtering units known as nephrons. The nephron includes a filter, referred to as the glomerulus, and a tubule.

• The nephrons function via a two-step process. The glomerulus allows fluid and waste products to pass through it; while on the other hand, it inhibits the movement of blood cells and large molecules, more often than not proteins, moving though them.

The filtered fluid subsequently passes through the kidney tubule or nephron, which returns the required minerals back to the bloodstream and eliminates wastes.

BIOLOGY: EXCRETORY SYSTEM

from Femosky110 on 06/11/2020 12:04 PM

The excretory system
The excretory system is a reflexive biological system that expels excess, needless materials from an organism, so as to help maintain homeostasis inside the organism and avert damage to the body.

 

It has the responsibility of eliminating the waste products of metabolism in addition to other liquid and gaseous wastes, like the urine and as a constituent of sweat and exhalation.

Since the majority of healthy functioning organs manufacture metabolic and other wastes, the whole organism relies on the function of the system; nevertheless, just the organs specially for the excretion process are taken as part of the excretory system.

biology
Parts of the excretory system and their function

1. Kidneys
The kidneys are bean shaped organs which are located in every one of the two sides of the Vertebral column in the abdominal cavity. Humans possess two kidneys and every one of them is supplied with blood from the renal artery.

Kidney expels the nitrogenous wastes from the blood like the urea and salts and excess water are as well expelled from the blood and excreted in the form of urine. This is made possible by the help of millions of Nephrons available in the kidney.

The filtrated blood is taken away from the kidneys by the renal vein or kidney vein. The urine from the kidney is gathered by the Ureter or excretory tubes, one among each one of the kidneys, and is taken to the Urinary bladder. Urinary bladder gathers and stores the urine till they are urinated.

The urine gathered in the bladder is excreted into the outside environment from the body via an opening known as the Urethra.

biology
The kidney's basic role is to remove waste from the bloodstream through urine production. They carry out many homeostatic functions like -

1. Maintaining the volume of extracellular fluid

2. Maintaining ionic balance in extracellular fluid

3. Maintaining the pH and osmotic concentration of the extracellular fluid.

4. Excreting toxic metabolic by-products like urea, ammonia, and uric acid.

The kidney does this through the 1 million nephrons contained in every kidney, these nephrons function as filters within the kidneys. The kidneys filter required materials and waste, the required materials pass back into the bloodstream, and un-required materials turn into urine and is eliminated.

In a few cases, excessive wastes turn into crystals as kidney stones. They grow and can turn into an aching pain that may need surgery or ultrasound treatments. A few stones are minute enough to be expelled via the urethra.

Liver
The liver detoxifies and breaks down chemicals, poisons and other toxins that get into the body. For instance, the liver transforms ammonia which is poisonous into urea which is subsequently filtered by the kidney into urine.

The liver as well manufactures bile, and the body makes use of bile to breakdown fats into utilizable fats and unusable waste.

Bile
After bile is manufactured in the liver, it is stored in the gall bladder. It is afterwards secreted inside the small intestine where it assists to break down ethanol, fats and other acidic wastes that include ammonia, into less harmful substances.

Large intestine
The large intestine gathers waste from all through the body. It extracts all the remaining utilizable water and subsequently eliminates solid waste. At approximately 10 feet long, it moves the wastes via the tubes to be excreted.

biology
Skin
The Skin excretes sweat via the sweat glands all through the body. This assists to expel additional wastes, like excess urine. Moreover, the sweat assisted by salt, escapes and helps to maintain the coolness of the body when the body gets warm.

Sweat glands in the skin secrete a fluid waste known as sweat or perspiration; although, its fundamental roles are temperature control and pheromone release. Therefore, its function as a component of the excretory system is negligible. Sweating as well regulates the level of salt in the body.

biology
Eccrine
Like sweat glands, eccrine glands allow excess water to escape from the body. A lot of eccerine glands are situated largely on the forehead, the bottoms of the feet, and the palms, even though the glands are all over the place in the body. They assist the body to retain its temperature control.

Lungs
One of the major roles played by the lungs is to diffuse gaseous wastes, like carbon dioxide, from the bloodstream as a typical part of respiration.

Ureter
The ureters are muscular tubes that thrust urine from the kidneys to the urinary bladder. In the human adult, the ureters are typically 25–30 cm (10–12 in) long. In humans, the ureters come up from the renal pelvis on the medial facet of every kidney prior to sliding towards the bladder on the front of the psoas key muscle.

The ureters pass over the pelvic brim next to the bifurcation of the iliac arteries. This "pelviureteric junction" is a widespread site that usually feels the impact of the kidney stones. Another site that feels the same impact is the uteterovesical valve.

The ureters dash posteriorly on the sideways walls of the pelvis. They after that bend anterior medially to go through the bladder via the back, at the vesicoureteric junction, passing within the wall of the bladder for some centimeters.

The backflow of urine is prohibited by valves referred as ureterovesical valves. In the female, the ureters pass via the mesometrium on the way to the bladder.

Urinary bladder
The urinary bladder is the organ that collects waste excreted by the kidneys prior to when they are eliminated via urination. It is a bare muscular, and distensible or elastic organ, and settles on the pelvic floor. Urine moves into the bladder via the ureters and to the exterior through the urethra.

Embryologically, the bladder is gotten from the urogenital sinus, and it is at first uninterrupted and with the allantois. In human males, the bottom of the bladder lies in between the rectum and the pubic symphysis.

It is superior to the prostate, and estranged from the rectum by the rectovesical dig. In females, the bladder lies inferior to the uterus and in front of the vagina. It is alienated from the uterus by the vesicouterine dig. In infants and young children, the urinary bladder is in the abdomen even when unfilled.

Urethra
In anatomy, the urethra is a tube which connects the urinary bladder to the exterior part of the body. In humans, the urethra has an excretory function both in male and in female.

Urine Formation
Inside the kidney, blood at first moves via the afferent artery to the capillary formation known as glomerulus and is gathered in the Bowman's capsule -located in the liver, which separates the blood from its contents—principally food and wastes.

After the filtration process, the blood subsequently goes back to gather the food nutrients it requires, while the wastes moves into the collecting duct, to the renal pelvis, and to the ureter, and are then after that excreted out of the body through the urinary bladder.

General features of excretory structures and functions
The physiological process by which organisms dispose of its nitrogenous by-products is known as excretion.

The meaning of excretion is for the most part simply understood in the perspective of vertebrate structure. The animal ingests food (ingestion). In the stomach and intestine a few of the food is converted into soluble products (digestion) that are assimilated into the body (assimilation).

In the body these soluble products experience additional chemical change (metabolism); a few are used by the body for growth, but the majority makes available energy for a variety of activities of the body.

Metabolism involves the intake of oxygen and the removal of carbon dioxide in the lungs (respiration).

Above and beyond carbon dioxide, compounds of nitrogen occur from metabolism and are done away with, mainly by the kidney, in the urine (excretion). Food not digested is expelled via the anus (defecation).

Products of excretion
Although every type of organism takes in a few materials and get rid of other, excretion is strictly a process seen in animals alone. For the purposes of this tutorial excretion will be taken to mean the removal of nitrogenous by-products and the regulation of the constituent of the body fluids.

The most important excretory product that occurs naturally in the animal body is ammonia, obtained roughly completely from the proteins of the ingested food. In the process of digestion proteins are converted into their component amino acids.

Some of the amino-acid pool is subsequently utilized by the animal to manufacture its own proteins, but a lot of it is utilized as a source of energy to compel other imperative processes.

The first step in the mobilization of amino acids for energy production is deamination, which means the removal of ammonia from the amino-acid molecule. The remaining is oxidized to carbon dioxide and water, with the associated manufacturing of the energy-rich molecules of adenosine triphosphate ATP.

The fact that excess levels of ammonia are extremely harmful to the majority of animals, they ought to be efficiently expelled. Minute aquatic animals do not have the same problem because ammonia swiftly diffuses, as a result of its high solubility in water into the surrounding water surfaces.

However in terrestrial animals, and in a few outsized aquatic animals, ammonia is transformed into varieties of less harmful compounds through the process known as detoxication.

In mammals, human being inclusive, it is detoxified to urea, which is taken to be produced through the condensation of a molecule of carbon dioxide with two molecules of ammonia.

Excretory mechanisms
biology
Vital information on the mechanism of Excretory System in Man

The human excretory system is made up of two kidneys that are bean shaped. The presence of two kidneys in human body is of a very big significance. When one kidney fails, the other can still perform the function of excretion.

The left kidney is situated a little higher than the right kidney. The kidneys are solid, reddish-brown, roughly 10 cm long organs which is situated in the abdominal cavity, one on each side of the vertebral column.

Every human kidney weighs about 150 g. The outer surface of the kidney is convex in shape while the interior is concave. There is a concave hollow known as hilus through which the arteries and veins pass into and leave the kidney.

Kidneys play a crucial role important role in regulating the composition of blood through the process known as osmo regulation.

Interesting points about excretion through kidney
• Roughly 130 ml of filtrate are produced every minute in the glomeruli of the two kidneys of man.

• Roughly 99% of the water of the filtrate is reabsorbed as it moves down the nephron.

• Body salts excreted in human urine may be about 2.2% and urea 6% of the volume of urine.

• The yellow colour of urine is as a result of a pigment called urochrome.

• Roughly1600 ml urine is excreted by an adult in 24 hours. A nephron is a 5-cm extended tubule.

• Urination is known as micturition. This is a reflex action (quick action) that is under the control of the spinal cord.

BIOLOGY: TISSUES SYSTEM

from Femosky110 on 06/11/2020 12:02 PM

Tissues and supporting system:
In biology, tissue is a cellular organizational level that is midway between cells and a complete multicellular organism. A tissue is a collection of similar cells from the identical origin that perform a particular function.

 

Organs in turn are obtained by a collection of several tissues. The study of tissue is referred to as histology and when tissue is studied with respect to disease, it is known as histopathology.

The standard tools for studying tissues are the paraffin block to which tissue is fixed and subsequently segmented, the histological stain, and the optical microscope.

In the past few decades, advancements in electron microscopy, immunofluorescence, and the utilization of frozen tissue sections have improved the feature that can be seen in tissues. With these tools, the standard looks of tissues can be studied in health and disease facilitates substantial enhancement of clinical diagnosis and prognosis.

Animal Tissue:
Animal tissues can be classified into four fundamental types: connective tissue, muscular tissue, nervous tissue, and epithelial tissue.

Several tissue types make up organs and body structures. Although all animals can by and large be well thought-out to have the four types of tissues, the appearance of these tissues can vary depending on the nature and form of the organism.

For instance, the source of the cells containing a specific type of tissue may vary in terms of development for a variety of animal classification.

The epithelium in all animals is the derivative of the ectoderm and endoderm with a little input from the mesoderm, structuring the endothelium, a specific kind of epithelium that comprises the vasculature.

On the contrary, a true epithelial tissue is only available in one layer of cells knitted together through occluding junctions referred to as tight junctions, to form a selectively permeable wall.

This tissue covers every surface of the organism that is exposed to the outside environment like you would obtain in the skin, the airways, and the digestive tract. Its sole function is for protection, secretion, and absorption. It is alienated from the rest of the tissues below by a lamina on the base.

Connective tissue
Connective tissues are composed of fibers. They are composed of cells divided by non-living substance referred to as an extracellular matrix. Connective tissue makes available shapes to organs and keeps them in place.

The blood and bone are examples of connective tissue. Just as you would deduce from the name, they support and connect other tissues. In contrast to the epithelial tissue, connective tissue characteristically has cells spread all through an extracellular matrix.

Muscular tissue
Muscle cells come together and form the energetic contractile tissue of the body referred to as muscle tissue or muscular tissue. Muscle tissue function is to generate force and cause movement, either locomotion or the movement of internal organs.

Muscle tissue is classified into three different categories: visceral or smooth muscle, which is created in the inner linings of organs; skeletal muscle, in which is found attached to bone making possible gross movement; and cardiac muscle which is seen in the heart, and which enables it to contract and pump blood all through the organism.

The muscular tissue is the most elongated group of cells in the human body.

Nervous tissue
The nervous or neural tissue is made up of all cells that made up the central nervous system and peripheral nervous system.

In the central nervous system, neural tissue come together to give rise to the brain and spinal cord while in the peripheral nervous system it forms the cranial nerves and spinal nerves in addition to the motor neurons.

Epithelial tissue
The epithelial tissues are made up of cells that envelop the organ surfaces like the surface of the skin, the airways, the reproductive tract, and the inner coating of the digestive tract.

biology
The cells that made up the epithelial layer are connected through semi-permeable, tight junctions; and so, this tissue acts as a boundary between the outside environment and the organ it covers. Apart from this protective function, epithelial tissue may as well be focused to perform secretion and absorptive function.

Epithelial tissue shields organisms from microorganisms, injury, and water loss. The functions of the epithelia tissue is listed below:

• the epithelia cell of the body surface form the outer layer of skin.

• Within the body surface, epithelial cells forms lining of mouth and alimentary canal and guard these organs.

• epithelial tissues assist in the absorption of water and nutrients.

• epithelial tissues assist in the removal of waste product.

Types of epithelia tissue
The various types of epithelial tissues are listed below:

• Squamous epithelium,

• Cuboidal epithelium,

• Columnar epithelium,

• Glandular epithelium,

• Ciliated epithelium.

Skeletal Tissue
The skeletal tissue is of three types. The three types of skeleton or skeletal tissue are hydrostatic skeleton, endoskeleton and exoskeleton. Hydrostatic skeleton is seen in cold-blooded animals in addition to invertebrates. Human beings have endoskeleton. Exoskeleton is available in insects.

Hydrostatic Skeleton
It is seen in soft-bodied and cold-blooded animals. This skeleton has a coelom, which is a fluid-filled cavity. The coelom is covered up by muscles and the stiffness initiated by the fluid and the muscles provide the supporting construction for the organisms.

The fluid pressure in addition to the motion of the supporting muscles assists the organisms to modify shape and move. Invertebrates, the greater part of the earth's living organisms are present in an enormous number of habitats.

They could be seen in the deepest part of the oceans to the thickest forests. These invertebrates possess a hydrostatic skeleton system that assists them to flourish in a different number of landscapes.

Echinoderms, cnidarians, annelids, nematodes and some other organisms use the hydrostatic skeleton for movement. The Earthworm which is an annelid has no bone. Through hydrostatic skeleton it makes hole through the ground. Examples of echinoderms are the star fish and the sea urchin. The Jelly fish is a cnidarians.

Endoskeleton
The simplest explanation for endoskeleton is that it is the skeleton located in the body. It forms the frame work for the animal. The tissues and muscles are produced around the skeletal system and the well-developed forces are passed on to this skeleton.

The Endoskeleton supports the animal constitution. It is made up of mineralized tissues. In Phylum Chordata, Porifera and Echinodermata endoskeleton is present.

Endoskeleton is created in the sub-class Coleoidae. The animals that belong to Phylum Chordata are all vertebrates in addition to human beings. Phylum Porifera are sponge-like animals and is made up of about 5000 species.

Its skeleton is a complex of organic fibres, a pedestal of calcite and aragonite and spicules of silica. Here the endoskeleton is for maintainance. Phylum Echinodermata is made up of a variety of symmetrical marine animals such as the star fish, sea urchins and so on. It has an endoskeleton composed of calcium and is enclosed with spines.

Echinoderms have endoskeleton because they have an interior calcareous skeleton. But for motion, it makes use of the tentacles which are comparable to a hydrostatic skeleton.

The endoskeleton in chordates and echinoderms are formed from mesodermal tissue and it is taken to be the true endoskeleton. In Coleoidae, the exoskeleton has evolved into the inner structure. Example is cuttle fish.

Exoskeleton
Exoskeletons are skeletons that exist outside the body. It forms a shielding covering for the animals. It supports and also protects the animals. All crustaceans possess exoskeleton. Crabs, spiders, lobsters, insects are all crustaceans.

Animals with exoskeleton are typically small. This is due to the fact that big animals could not be sustained by exoskeleton and need bones to hold them up. Animals with exoskeleton possess a head and abdomen and in a number of cases, a thorax.

The exoskeleton is supple and thin at the joints where it ought to bend. The outsized exoskeletons are referred to as shells. Tortoise is an animal that has a shell and endoskeleton.

The simplest type of skeleton is the hydrostatic skeleton obtained in a lot of cold-blooded organisms and soft-bodied animals. The pressure of the fluid and action of the adjoining muscles are used to alter an organism's figure and generate movement. This fluid filled cavity is referred to as the coelom.

The human Skeletal System
biology
The supporting tissues of animals which frequently serve as a protection for the body or parts of it and play a crucial role in the animal's physiology is known as skeleton.

Skeletons can be divided into two major types in relation to the comparative location of the skeletal tissues. When these tissues are situated outside the soft parts, the animal is said to possess an exoskeleton.

If they take place deep inside the body, they constitute an endoskeleton. All vertebrate animals have an endoskeleton, but the majority as well has components that are exoskeletal in origin. Invertebrate skeletons, nonetheless, demonstrate far more disparity in position, morphology, and materials used to assemble them.

The vertebrate endoskeleton is typically made up of bone and cartilage; with the exception of a few fishes that possesses skeletons that do not have bone.

In addition to an endoskeleton, a lot of species have distinct exoskeletal structures composed of bone or horny materials. This dermal skeleton makes available support and safeguard at the body surface.

A lot of structural components constitute the human skeleton, which includes the collagen, three diverse types of cartilage (hyaline, fibrocartilage, and elastic, as well as a lot of bone types-woven, lamellar, trabecular, and plexiform.

The vertebrate skeleton is made up of the axial skeleton –the skull, vertebral column, and related structures and the appendicular skeleton which consists of limbs or appendages. The essential plan for vertebrates is comparable, though great variations take place in relation to functional demands placed on the skeleton.

Axial skeleton
The axial skeleton provides support for the organs of the head, neck, and torso and as well offers them protection. In humans, the axial skeleton is made up of the skull, ear ossicles, hyoid bone, vertebral column, and rib cage.

Skull
The adult human skull is made up of eight bones which make up the cranium, or brain box, and 13 facial bones that sustain the eyes, nose, and jaws. There are as well three small, paired ear ossicles—the malleus, incus, and stapes—inside a hollow in the temporal bone.

The totality of 27 bones represents a huge drop in skull elements all through the course of vertebrate advancement. The three components of the skull are the neurocranium, dermatocranium, and visceral cranium.

The brain and certain sense organs are sheltered by the neurocranium.

Every vertebrate neurocrania grow in the same way, beginning as ethmoid and basal cartilages beneath the brain, and as capsules partially encircling the tissues that finally form the olfactory, otic, and optic sense organs. Additional growth manufactures cartilaginous barricades around the brain.

Vertebral column
The vertebral column is an endoskeletal segmented shaft of mesodermal derivation. It protects the spinal cord, acts as sites for muscle attachment, offers flexibility, and support, especially in land-based tetrapods where it has to maintain the weight of the body.

Hard, spool-shaped bony vertebrae exchange with tough but flexible intervertebral discs. Every typical vertebral body (centrum) has a bony neural arch extending dorsally. The spinal cord pass through these arches, and spinal nerves come out through the spaces.

BIOLOGY: CELL PROPERTIES

from Femosky110 on 06/11/2020 12:00 PM

The Properties of the Living Cell
A cell is the smallest unit of life. The cell is the beginning point for every organism. A few living things like bacteria are made up of one cell, while a complex organism like the human body is made up of trillions of cells.

 

In the multicellular animals, a group of cells makes up tissues, and a group of tissues which make up organs, which in turn make up organ systems, which also come together to make the complete animal. Without the cells we would not exist.

The cell is made up of three basic components of all cells: an outer cell membrane, an inner nuclear region, and the cytoplasm which is found in between them. Cellular biology is one aspect of biology that is hugely studied.

Cells are very significant because they carry out all of life's functions. Without cells, we would not even be able to shift a muscle, for the fact that the reactions that are required to allow it to happen would be absent.

biology
Nutrition in Plants
Classification of plants on the basis of mode of nutrition:
Plants can be divided into two groups on the basis of their mode ofXThe two groups are:

1. Autotrophic or autotrophs

2. Heterotrophic or heterotrophs

Heterotrophic nutrition is the type of nutrition obtained by digesting organic compounds. Animals, fungi, a lot of prokaryotes and protoctists which are incapable of synthesizing organic compounds for their food, feed heterotrophically. They are thus referred to as heterotrophs.

Holozoic nutrition is a form of heterotrophic nutrition which requires dependence.

Parasitic nutrition is a mode of heterotrophic nutrition where an organism lives on the body surface or inside the body of another type of organism

1. Autotrophic nutrition
Autotrophic nutrition is the type of nutrition in which organic compounds are manufactured from available inorganic raw material obtained from the environment. In autotrophic nutrition, the nutrients do not require to be broken down or digested before they are taken into the cells.

Two methods of autotrophic nutrition
On the basis of source of energy, autotrophic nutrition can be further divided into the sub-types listed below:

(I) Phototrophic nutrition

(II) Chemotrophic nutrition

I. Phototrophic nutrition:
Phototrophic nutrition is the form of autotrophic nutrition in which organic molecules are produced from uncomplicated inorganic molecules with the help of energy obtained from sunlight.

Example of phototrophic nutrition can be seen in:

a. Green Plants

b. Photosynthetic Bacteria

Phototrophic nutrition as obtained in green plants
Green plants are well-known example of phototrophic nutrition. Green plants manufacture their own food through the process of photosynthesis. The materials necessary for photosynthesis to occur are:

CO2 and H20
Carbon dioxide and water make available carbon, hydrogen and oxygen which are required for the synthesis of organic molecules.

Minerals
The minerals such as Nitrogen, Phosphorus and Sulphur and Magnesium are also essential for photosynthesis to take place.

The Chlorophyll:
The green pigments known as Chlorophyll is as well necessary for photosynthesis to take place. It is essential to absorb the energy from the sun which is the universal source of light.

The sunlight :
In the presence of sun light, the above mentioned nutrients are used to synthesize the energy rich compound known as (CHO). This process is known as photosynthesis.

Photosynthesis can be represented through the following equation:

6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O

Phototrophic nutrition in photosynthetic bacteria
Photosynthetic bacteria are inimitable due to the fact that they are the only organisms that have the capacity to synthesize carbohydrate food in the absence of chlorophyll.

Differences between photosynthetic bacteria and green plants
Photosynthesis in bacteria differs from that of green plants. Some differences between them are

Photosynthetic bacteria normally grow in sulphide spring which usually contains H2S.

The hydrogen used in the synthesis is obtained from H2S as opposed to water - H2O in green plants.

In bacteria photosynthesis, oxygen is not liberated to the surrounding as a byproduct.

The process of bacteria photosynthesis occurs with a little release of energy.

Two types of photosynthetic bacteria:
There are two types of photosynthetic bacteria. The first group releases sulphur "S" as a bye product. This type of bacteria gets the hydrogen for the synthesis from H2S. The energy from the light divides into hydrogen ion and sulphide ion. Hydrogen reacts with CO2 to form H2O as shown in the equation below:

2H2S + CO2 -> (CH2O)n + H2O + 2S

Example of such bacteria is the Purple Sulphur Bacteria which make use of bacterio chlorophil and caretenoid as the pigments for photosynthesis.

The second group of photosynthetic bacteria is those who do not release sulphur "S" as the by-product. These bacteria make use of H2S as the donor of hydrogen but sulphur is not released as a by-product.

Examples of this type of bacteria are the purple non-sulphur bacteria and the brown non-sulphur bacteria. Both of them have "bacterio chlorphyll" as their photosynthetic pigments.

Chemotrophic nutrition:
Chemotrophic autotrophic nutrition is the type of autotrophic nutrition where organic molecules are produced from simple inorganic molecules through the use of energy obtained from the oxidation of a few inorganic substances like ammonia, nitrates, nitrites, ferrous ions, H2S and so on.

This type of nutrition is known as chemotrophic nutrition and process of manufacturing food in this manner is referred to as chemosynthesis.

Example of organism that does chemosynthesis is the bacteria like ammonia using bacteria. They obtain their energy by oxidizing Ammonia as illustrated in the equation below:

NH4+ + O2 -> 2NO2 + 2H2O + 4H+ + energy

Another type of bacteria which converts nitrites to nitrate does it through the process of chemosynthesis as shown in the equation below:

2NO2 + O2 -> 2NO3- + energy

Importance of chemosynthetic bacteria:
The chemosynthetic bacteria that act on nitrogen compounds play a crucial role in nitrogen cycle and ensure that a balance of nitrogen is sustain in the life system.

2. Hetertrophic Nutrition in Plants
Plants which are not able to manufacture their own food completely or partially and are dependent on other in order to get their organic molecules are referred to as heterotrophic plants.

Classification of heterotrophic plants
On the basis of type of organisms on which heterotrophic plants depend on for the synthesis of their organic molecules, they can be divided into the two classes below:

• Parasitc Plants Or Parasites

• Saprophytic Plants Or Saprophytes

1. PARASITES
These are heterotrophic plants that depend on living plants and animals for their nutritional requirements.

Types of parasites
Parasitic plants can be further divided into the following types.

• Obligate or total parasites.

• Facultative or partial parasites.

Total parasites are those parasites which depend on other organism entirely for their food or organic materials.

Total parasites are further classified into two:

1. Total stem parasite

2. Total root parasite

1. Total stem parasites are the category of parasitic plants that depend entirely on the stem of other plants for their food. These plants propel a structure called haustoria which is a special structure used in the absorption of nutrients in parasitic plants inside the tissue of host.

The xylem of the parasite comes in contact with the xylem of host and the phloem of the parasite to the phloem of the host. Through the xylem it draws up the water and nutrients and through the phloem, it draws up prepared organic material.

This eventually leads to the death of the host plant as a result of exhaustion. Example of such parasite is the cuscuta (amer-bail)

2. Total root parasites:

These are parasitic plants which draw up their nutritional requirements from the roots of host. Examples are:

1. Orobanche- This normally attacks the roots of the plants that belonged to the families -Cruciferae and Solanaceae.

2. Cistanche - These Parasitizes attacks the roots of Calatropis.

3. Striga – These parasites are found on the roots of sugar cane

Partial parasites
These are those parasitic plants which depend partially on other organism for their nutritional value.

Classes of partial parasitic angiosperms:
Partial parasitic angiosperms can be generally classified into

1. Partial stem parasite

2. Partial root parasite

1. Partial stem parasites
Partial stem parasites are those parasites whose their haustoria penetrate into the stem of the host and to suck their nutrition from vascular tissues of stem.

2. Partial root parasites
The example of this category of parasite although uncommon is the sandle wood tree

Saprophytes
Saprophytes are plants that depend on dead or rotten organic remains of plants or animals for their food or nutritional intake. Also plants which decompose composite dead food material into simple compounds and make use of them for their nutrition, growth and development are referred to as saprophytes.

Types of Saprophytes
Saprophytes can be sub divided into two namely:

1. Total Saprophytes

2. Partial Saprophytes

Total saprophytes
This group of saprophytes depends totally on dead organic material for their nutritional value.

Partial saprophytes
These are type of saprophytes which depend partly on dead organic matter for their nutritional value.

Examples of saprophytes
There are a few examples of Saprophytes amongst flowering plants.

1. Neothia -bird's net or orchid

2. Monotrapa- Indian Pipe

In these two cases, the roots of plant form a Mycorhizzal Association with fungal mycelium to assist them in the absorption process.

Special mode of nutrition
Carnivorous or insectivorous plants
Carnivorous or insectivorous plants are plants which have as their prey, insects and small birds. This is a special mode of nutrition in partially autotrophic and partially heterotrophic plants.

Partially autotrophic and partially heterotrophic plants are carnivorous plants which has the green pigments and can produce CHO but are not able to synthesize nitrogenous compounds and proteins.

In order to get their nitrogen requirement, carnivorous plants depend on insects, which they trap and digest through particular devices developed in them.

Cellular respiration
This is the set of the metabolic reactions and processes that occur in the cells of organisms to transform the biochemical energy from nutrients into adenosine triphosphate (ATP), and after that releases waste products.

The reactions that are required in respiration are catabolic reactions, which split large molecules into smaller ones, with the release of energy in the process where the weak "high-energy" bonds are replaced by stronger bonds in the products.

Respiration is among the main ways a cell gains helpful energy to fuel cellular activity. Cellular respiration is taken as an exothermic redox reaction. The general reaction is converted into a lot of smaller reactions when it takes place in the body, the majority of which are redox reactions themselves.

Even though in principle, cellular respiration is a combustion reaction, it obviously does not bear a resemblance to one when it takes in a living cell. This variation is due to the fact that it takes place occurs in a lot of detached steps.

While on the whole, the reaction is a combustion reaction, no particular reaction that it is composed of is a combustion reaction.