Category: Biology

Green plants make food by a chemical process called photosynthesis. Photosynthesis is a process of capturing and transforming the energy of sunlight into chemical energy. Plants usecarbon dioxideand water to make glucose and release oxygen. Respiration on the other hand is a chemical process in which food is oxidized in an organism to produce energy for cell activities.

CHEMISTRY OF PHOTOSYNTHESIS

How much do you value green plants? Do you agree that we depend on plants for many things directly and indirectly? Green plants capture the energy of sunlight and transform it into chemical energy. This chemical process of capturing and transforming the energy of sunlight into chemical energy is called photosynthesis. This is the mechanism through which plants manufacture their own food by using water, carbon dioxide and sunlight absorbed by chlorophyll.

Through osmosis water is absorbed from the soil and transported to the green leaves where photosynthesis takes place. The most abundant and important photosynthetic pigment is chlorophyll. Green plants contain chlorophyll. Chlorophyll is the green pigment in plants.Carbon dioxidefrom the atmosphere diffuses into the leaf directly. It absorbs sunlight as a source of energy for the mechanism of photosynthesis to succeed. Photosynthesis takes place in the chloroplasts which are found mainly in the leaves.

The mechanism of photosynthesis is in two stages; light reaction (Kelvin reaction) and dark reaction.

1.Light reaction

During day time plants absorb sunlight using chlorophyll. In the leaf, light energy is converted into chemical energy. It is this chemical energy which is used to split water into hydrogen andoxygen. This reaction is reversible. It is during this reaction that oxygen is produced. The reaction is light controlled. It is sometimes called Calvin reaction because it was discovered byMelvin Calvin(1911-1997).

2.Dark reaction

In the second reaction the hydrogen from water chemically combines with carbon dioxide to form glucose. The process is long. This reaction is enzyme controlled and not light controlled. This is the reason why it is called dark reaction.

The chemical equation is as written below:

Factors necessary for photosynthesis to take place arecarbon dioxide, water, light and chlorophyll. Sugar and oxygen are the products of this chemical reaction.

Oxygen is essential for living organisms because it is used in respiration. Respiration is the process by which living cells produce energy from the combination of foods, such as glucose, with oxygen. The oxygen is released as a waste product. The sugar is used in three ways:

i. Converted into starch and transported to other partsof the plant, in some plants it is stored in tubers or stems as food.

ii. Converted into cellulose for the cell walls.

iii. Used by the plant for its own respiration to provideenergyfor other processes.

In addition, plants use glucose molecules made from photosynthesis as a starting point for making other more complex substances which are passed on in the food chain when plants are eaten by animals.

EXPERIMENT 1

How to test for starch in a leaf?

First of all, we have to suggested materials to use in this test. Here is the list of materials to use: A leaf, alcohol, boiling tube, beaker, water, tripod stand, wire gauze, spirit burner or Bunsen burner, Petri dish, test tube, test tube rack, iodine solution, dropper, and forceps.

Once we have the materials, then we plan how to carry out this test. This is called the method or procedure of the test. The method (procedure) is as follows:

a. Detach a leaf from a plant that has been exposed to light and boil it in water for 1 to 4 minutes to make it soft and to stop the chemical reaction.

b. Boil the leaf in alcohol using a water bath to remove chlorophyll

c. Wash the leaf in warm water to remove alcohol and to make it soft since alcohol makes the leaf brittle.

A. Spread the bleached leaf on a white tile and add drops of iodine solution. Theiodine solutionturns blue/black if starch is present in the leaf.

EXPERIMENT 2

AIM

To show that oxygen is given out during photosynthesis

MATERIALS

Test tube and rack, wooden splint, pond weed, distilled water, sodium hydrogencarbonate, spatula, 250 cm³beaker, filter funnel and plasticine.

PROCEDURE

a. The apparatus is set as shown above. Sodium hydrogencarbonate is added to the water to increase the availability of carbon dioxide.

b. The whole experiment is left in a well-lit place for a number of days and observation goes on.

RESULTS

Bubbles of a gas are released from the plant and collect in the test tube.

Observation:
Bubble of gas was noticed in experiment A. On passing a glowing splint over it, the splint was rekindle. In the set-up B, no bubbles were seen, and it could not rekindle a glowing splint.

Conclusion:

The gas that evolved in A is oxygen because, it is a known test for oxygen that oxygen rekindles a glowing splint.

CONCLUSION

When the gas is tested with a glowing splint of wood, it relights. This shows that the gas is oxygen.

3.Factors that affect the rate of photosynthesis

The following factors have an effect on the rate of photosynthesis in green plants:

a. Light intensity

b. Carbon dioxide concentration

c. Temperature

d. Availability of water

Planning your own experiments

Use your knowledge of photosynthesis to plan experiments to show that carbon dioxide, chlorophyll, and light are necessary for photosynthesis. Each experiment will need a control. Here is an example:

AIM

To show that light is necessary for photosynthesis.

MATERIALS

PROCEDURE

a. The plant is left in the dark for 24 hrs before the experiment starts to remove the starch. This is called de-starching.

b. It is removed from the dark and put in sunlight for 24 hours but with part of the leaf covered by an aluminium foil. What is the role of aluminium foil in the experiment above?

Holt in foil

c. The leaf is then tested for the presence of starch.

RESULTS

The parts covered by the aluminium foil does not show the presence of starch but the part where there was a hole the iodine solution changes colour from yellow to blue black showing that starch is present.

CONCLUSION

This showed that starch was made in the presence of light but not where the leaf remained in the dark.

4.Importance of photosynthesis

To all animals, photosynthesis is very important. The sun is the main source of energy on which all creation depends. However, it is only plants that can utilize this energy. When plants are eaten energy is transferred to other forms. All heterotrophs depend on plants for energy. Even when dead remains of plants decay, energy is never lost but changed into another form which is nutrients in the soil. In conclusion we would say that all animals depend on photosynthesis as they depend on plants.

5.Photosynthesis and cellular respiration

Respiration involves a complicated chain of chemical breakdown of food to release energy. The energy produced is used for many chemical reactions in the living cell. There are two types of respiration – aerobic and anaerobic. Aerobic respiration involves the use of oxygen in the breakdown of glucose while anaerobic respiration does not use oxygen. Here we will look at aerobic respiration in plants.

Photosynthesis is the reverse of cellular respiration. Cellular respiration is the name given to the processes in cells that releases energy from food. Plants also use glucose molecules made from photosynthesis as starting point for making other more complex substances. These two chemical processes take place simultaneously in light in plants.

However, respiration takes place in the cytoplasm and mitochondria while photosynthesis takes place in the chloroplasts. In respiration, glucose and oxygen are used to produce carbon dioxide and water and release energy. In photosynthesis, carbon dioxide, water, and energy are used to produce glucose and to release oxygen. Cellular respiration releases chemical energy while photosynthesis captures light energy.

The chemical equation for cellular respiration is:

C₆H_l20₆+ 60₂⟶ 6CO₂+ 6H₂O + energy

The word equation is:

Glucose + Oxygen → Carbon dioxide + Water + Energy

From the equation above, it is clear that for respiration to take place, food and oxygen must be taken in and reacts together. The end products of respiration carbon dioxide and water must be removed constantly.

It is important for the farmers to understand the most commonanimal diseasesso as to identify them early and have idea on how to treat them.

Good husbandry, proper feeding, and hygiene are the main contributors to animal health on the farm, bringing economic benefits through maximisedproduction. When, despite these precautions, animals still become sick, they are treated with veterinary medicines, by the farmer and the veterinarian. When farmers treat their own animals, they are required to follow the guidelines for treatment and to record the treatments given.

Animals are susceptible to a number of diseases and conditions that may affect their health. Some, like classical swine fever and scrapie are specific to one type of stock, while others, like foot-and-mouth disease affect allcloven-hoofedanimals. Where the condition is serious, governments impose regulations on import and export, on the movement of stock, quarantine restrictions and the reporting of suspected cases.

Vaccines are available against certain diseases, and antibiotics are widely used where appropriate. At one time, antibiotics were routinely added to certain compound foodstuffs to promote growth, but this practice is now frowned on in many countries because of the risk that it may lead to antibiotic resistance. Animals living under intensive conditions are particularly prone to internal and external parasites; increasing numbers ofsea liceare affecting farmed salmon in Scotland. Reducing the parasite burdens of livestock results in increased productivity and profitability.

1.Anthrax

Anthrax, a highly infectious and fatal disease of cattle, is caused by a relatively large spore-forming rectangular shaped bacterium called Bacillus anthracis. Anthrax causes acute mortality in ruminants. The bacteria produce extremely potent toxins which are responsible for the ill effects, causing a high mortality rate. Signs of the illness usually appear 3 to 7 days after the spores are swallowed or inhaled. Once signs begin in animals, they usually die within two days.

Hoofed animals, such as deer, cattle, goats, and sheep, are the main animals affected by this disease. They usually get the disease by swallowing anthrax spores while grazing on pasture contaminated (made impure) with anthrax spores. Inhaling (breathing in) the spores, which are odorless, colorless, and tasteless, may also cause infection in animals and people.

Symptoms:

• Sudden death (often within 2 or 3 hours of being apparently normal) is by far the most common sign;
• Very occasionally some animals may show trembling, a high temperature
• Difficulty breathing, collapse and convulsions before death. This usually occurs over a period of 24 hours;
• After death blood, may not clot, resulting in a small amount of bloody discharge from the nose, mouth and other openings

Treatment and control

• Due to the acute nature of the disease resulting in sudden death, treatment is usually not possible in animals even though Anthrax bacilli are clines. Treatment is of use in cases showing sub-acute form of the disease.
• In most cases, early treatment can cure anthrax. The cutaneous (skin) form of anthrax can be treated with common antibiotics.

Preventive measures:

• Regular annual vaccination of animals in endemic areas will prevent the disease from occurring.
• Vaccination may be carried out at least a month prior to expected disease occurrence in endemic areas.
• Never open a carcass of an animal suspected to have died from anthrax.
• Contact a veterinarian immediately if the following symptoms are seen and seek advice on control measures to be adopted.

2.Black quarter (black-leg)

It is an acute infectious and highly fatal, bacterial disease of cattle. Buffaloes, sheep and goats are also affected. Young cattle between 6-24 months of age, in good body condition are mostly affected. It is soil-borne infection which generally occurs during rainy season. In India, the disease is sporadic (1-2 animal) in nature.

Causal organism

it is a bacterial disease caused by Clostridium chauvoei

Symptoms:

• Fever (106-108°F), Loss of appetite, Depression and dullness
• Suspended rumination
• Rapid pulse and heart rates
• Difficult breathing (dyspnoea)
• Lameness in affected leg
• Crepitation swelling over hip, back & shoulder
• Swelling is hot & painful in early stages whereas cold and painless inter.
• Recumbency (prostration) followed by death within 12-48 hrs.

Treatment:

• Early treatment can be possible to complete cure of the animal.
• Consult with veterinarian immediately.

3.Rabies (Mad dog disease)

Rabiesis a disease of dogs, foxes, wolves, hyaenas and in some places, it is a disease of bats which feed on blood.

The disease is passed to other animals or to people if they are bitten by an animal with rabies. The germs which cause rabies live in the saliva of the sick (rabid) animal. This is a killer disease but not every dog which bites is infected with rabies.

When the rabid animal bites another animal or human, the germs which live in its saliva pass into the body through the wound caused by the bite. The germs travel along the nerves to the brain. The time between the bite and the first appearance of signs that the bitten animal or human has been infected can take from 2 to 10 weeks or more. The time taken depends on the distance of the bite from the brain. If the bite is on the face or head, the bitten animal or human will quickly show signs, but if the bite is on the leg it will take much longer for signs to develop.

General signs of rabies

You should first look for the marks of the bite and discover where and when the animal was bitten. All rabid animals show similar signs in the beginning.

• they change their normal behaviour and behave very strangely.
• They stop eating or drinking.
• Male animal will try to mate (mount) other animals.
• there is no change in the body temperature.
• These signs will continue for 3 to 5 days. Then, before it dies, the animal will develop one or the other of two types of the disease:
• the furious (mad) type of the disease makes the animal aggressive and it will bite anything.
• The quiet (dumb) type when the animal is quiet and does not move.

Rabies in the dog

Dogs show either of the two types of rabies.

• a dog with the dumb or quiet type of the disease cannot move. It looks as if it has a bone stuck in the mouth and saliva drips from the mouth.
• rabies in the dog lasts about 10 days before the animal dies. If the animal does not die after this length of time then it may not be suffering from rabies.

Rabies in sheep, goats and cattle

Rabies is characterised by the animals becoming restless and excited. They may bite themselves and saliva drips from the mouth. The most important sign in cattle is that the animal bellows (calls) very frequently and with strange sound. The animals will become paralysed and die.

Rabies in the horse and camel

The horse will show the furious (mad) type of the disease. It will kick and bite and show signs similar to colic. The animal will die after paralysis of the back legs.

In the camel the signs of rabies are similar to those shown by an animal in the rut.

What to do with a biting dog

Remember that not every dog which bites has rabies. If the dog belongs to somebody ask the owner about its normal behaviour. If the dog is showing signs of rabies you must inform your veterinary officer immediately. The dog must be shot and if it has bitten anybody, they must be taken to a hospital immediately for vaccination.

Control of rabies

Dogs in your community can be vaccinated against rabies. You should ask your veterinary service about vaccination against rabies. If there is an outbreak of rabies, the livestock in your community can be vaccinated too.

Treatment (ethnovet practices) :

Leaves of chirchra (Achyranthes aspera) 100gm and onion 50 gm are ground well and smeared over the bitten place. The extract of these ingredients is administered orally twice in a day.

4.Blue tongue

Bluetongue, a disease which is transmitted by midges, infects domestic and wild ruminants and also camelids, however sheep are particularly badly affected. Cattle, although infected more frequently than sheep, do not always show signs of disease. Virus spreads between animals occurs via the midges of Cullicoides species.

The likelihood of mechanical transmission between herds and flocks, or indeed within a herd or flock, by unhygienic practices (the use of contaminated surgical equipment or hypodermic needles) may be a possibility.

Clinical signs

Sheep : eye and nasal discharges, drooling, high body temperature, swelling in mouth, head and neck, lameness and wasting of muscles in hind legs, haemorrages into or under skin, inflammation of the coronary band, respiratory problems, fever, lethargy.

In cattle: nasal discharge, swelling of head and neck, conjunctivitis, swelling inside and ulceration of the mouth, swollen teats, tiredness, saliva drooling, fever.

Note: a blue tongue is rarely a clinical sign of infection

Control

Inspect stock closely, particularly focusing on the lining of the mouth and nose and the coronary band (where the hoof stops and the skin starts). If an animal is suspected as having bluetongue, it must be reported as quickly as possible. Telephone your local animal health office immediately.

Preventive measures and treatment (ethovet):

Since the animal is not taking any feed the starvation may lead to death. So the animal has to be administered orally the following food. Banana fruits (one) smeared with sesame oil (50 ml) for 2 to 3 times. By this animal will recover little. However, this will not control the disease fully. Next the leaf pulp of “sothukathalai”(Aloe vera) has to be administered daily.

Administering of Aloe vera has to be continued for more days till the animal fully recovers from this disease. By this treatment the infected animal will recover from the disease. The disease will not spread to other animals if all animals are administered with Aloe vera as a preventive treatment. Administering aloe vera also increases the body weight of animals as it is against all intestinal parasite.

5.Pox

Epidemiology : sheep-pox is a highly contagious disease. It causes a mortality of 20 to 50 per cent in animals below the age of 6 months, and causes damage to the wool and skin in adults. Of the pock diseases, sheep-pox ranks only second to human small-pox in virulence. The disease is transmissible to in-contact goats but not to other species of animals. It, however, spreads slowly.

Symptoms : The disease in characterized by high fever, and symptoms of pneumonia and acute enteritis. Skin lesions appear particularly in parts free from wool, notably around the eyes, inner side of the thigh, udder and under surface of the tail. The internal organs such as trachea, lungs, kidneys and intestines are also affected. The disease results in emaciation and, as already mentioned, frequent deaths of affected animals.

Treatment, prevention and control

The diseased animal should be treated with palliatives. In the young ones nursing is more important than medication. The infected litter should be burnt and the bedding changed every day. Affected animals should be kept on soft diet. The ulcers on the skin should be washed with potassium permanganate lotion and dusted with boric acid; strict hygienic measures should be adopted.

Preventive measures and treatment (ethnovet)

External application of paste prepared by grinding neem leaves, tulsi leaves each 100 gm and turmeric powder- 50gm sprinkled with sufficient water. Continue for 3 to 5 days. Administer orally the same mixture by diluting with water.

6.Tetanus

This is an infectious, non-febrile disease of animals and man, and is characterized by spasmodic tetany and hyperaesthesia. This disease is prevalent all over the world.

Transmission

Infection takes place by contamination of wounds. Deep punctured wounds provide favourable conditions for the spores to germinate, multiply and produce toxin which is subsequently absorbed in the animal body. The micro-organism is present in soil and in animal faeces, and is carried into the wound by a penetrating object. The organism is present in the intestine of normal animals, and under some undetermined conditions multiplies rapidly and produces toxin in sufficient quantities to be absorbed and cause the disease.

Symptoms

The incubation period is generally 1-2 weeks but it may be as short as 3 days. Tetanus affects many species of domesticated animals but occurs particularly in horses and lambs; less frequently in adult sheep, goats, cattle, pigs, dog and cats; and rarely in poultry. The initial symptoms are mild stiffness and an unwillingness to move all the animals. More severe symptoms develop after 12-24 hours which are stiffness of limbs, neck, head, tail and twitching of muscles. The spasms develop in response to noise. In terminal stages ears are erect, nostrils dilated, nictitating membrane protruded. Mastication becomes very difficult because mouth cannot be opened, hence the name lockjaw.

Treatment

The treatment is carried out by first injecting antitoxin then treating the wound. Penicillin parenterally is beneficial. Muscular relaxation is achieved by injection of relaxants. The animal should be kept in a dark room and fed with the help of stomach tube.

Control

Proper hygiene and cleanliness at castration and other surgical procedures should be observed. Sheep should be given 2 injections based 3 weeks apart to develop a solid immunity.

7.Johne`s disease

Johne`s disease is a specific chronic contagious enteritis of cattle, sheep, goat, buffaloes and occasionally of pigs. The disease is characterized by progressive emaciation and in cattle and buffaloes by chronic diarrhea and thickening of the intestine.

Transmission

Under natural conditions the disease spread by ingestion of feed and water contaminated by the faeces of infected animals. The infection occurs mostly in the early month of life. The incubation period extends from 12 months to several years. The animal aged 3 to 6 years mostly suffer from the disease. Affected animals may not show clinical symptoms continue to discharge organisms in faeces.

The organisms persist in pastures for about 1 year. The organisms are susceptible to sunlight, drying and high ph of soil; continuous contact of urine with faeces reduces the life of bacteria. In cattle clinical signs appear mainly during 2-6 years of age. The infected animals which are apparently healthy, often show clinical signs after parturition.

Treatment

the organisms is more resistant to chemotherapeutic agents invitro than mycotuberculosis. Because of this the practical utility of treatment in clinical cases is poor.

Control

The affected animal should be segregated and their faeces properly disposed off. Alive vaccine has been developed. It reduces the incidence of clinical disease. It consists of a non-pathogenic strain of jhone`s bacillus with an adjuvant. The calves soon after birth are inoculated with vaccine subcontaneously. The vaccinated animals become reactors of jhonin. Vaccination is generally done in heavily infected herds.

8.Footrot

Foot rot is a common cause of lameness in cattle and occurs most frequently when cattle on pasture are forced to walk through mud to obtain water and feed. However, it may occur among cattle in paddocks as well, under apparently excellent conditions.

Foot rot is caused when a cut or scratch in the skin allows infection to penetrate between the claws or around the top of the hoof. Individual cases should be kept in a dry place and treated promptly with medication as directed by a veterinarian.

If the disease becomes a herd problem a foot bath containing a 5% solution of copper sulphate placed where cattle are forced to walk though it once or twice a day will help to reduce the number of new infections. In addition, drain mud holes and cement areas around the water troughs where cattle are likely to pick up the infection. Keep pens and areas where cattle gather as clean as possible. Proper nutrition regarding protein, minerals and vitamins will maximize hoof health.

9.Bovine rhinotracheitis

Infectious bovine rhinotracheitis (ibr) is a highly contagious, infectious respiratory disease that is caused by bovine herpesvirus-1 (bhv-1). It can affect young and older cattle. In addition to causing respiratory disease, this virus can cause conjunctivitis, abortions, encephalitis, and generalised systemic infections. Ibr is characterized by acute inflammation of the upper respiratory tract.

Treatment

There is no direct treatment for viral diseases. Infected animals should be isolated from the rest of the herd and treated with anti-inflammatory drugs and antibiotics for secondary infections if necessary. Carrier cattle should be identified and removed from the herd.

Prevention

Control of the disease is based on the use of vaccines.

10.Ringworm

This is the most common infectious skin disease affecting beef cattle. It is caused by a fungus, and is transmissible to man. Typically, the disease appears as crusty grey patches usually in the region of the head and neck and particularly around the eyes.

As a first step in controlling the disease, it is recommended that, whenever possible, affected animals should be segregated and their pens or stalls cleaned and disinfected. Clean cattle which have been in contact with the disease should be watched closely for the appearance of lesions and treated promptly.

Proper nutrition, particularly high levels of vitamin a, copper and zinc while not a cure, will help to raise the resistance of the animal and in so doing offer some measure of control. Contact your vet and or feed store for products to treat this disease. Using a wormer like ivomec will kill lice and help prevent cattle from scratching causing skin damage and a place for the fungus to enter.

The Human brain, a jelly-like substance, is the most important body part and is located inthe head, right under the skull. It is protected by a fluid and the skull (the bone part of the head). The anatomy and the functioning of the brain differ from one animal to another in a lot of different ways. With the help of our brain we can survive (through automatic processes like breathing), think, love, create and remember.

The brain is connected to the entirebodythrough nerves, composing together the nervous system and making other body organs act. For example: when we see an object coming fast towards us, theeyes send the image to the brain. After the information is processed, the brain sends commands through the nerves to our muscles, making our body dodge. More functions of the human brain include muscle control and coordination,sensory receptionand integration, speech production, memory storage, and the elaboration of thought and emotion.

Brain Structure

The brain is one of the largest and most complex organs in the human body. It is made up of more than 100 billion nerves that communicate in trillions of connections calledsynapses. The human brain is made up of many specialised areas that work together:

• The cerebral cortex is the outermost layer of brain cells. Thinking and voluntary movements begin in the cortex.
• The brain stem is between the spinal cord and the rest of the brain. Basic functions like breathing and sleep are controlled here.
• The basal ganglia are a cluster of structures in the centre of the brain. The basal ganglia coordinate messages between multiple other brain areas.
• The cerebellum is at the base and the back of the brain. The cerebellum is responsible for coordination and balance.

The brain is also divided into several lobes:

• The frontal lobesare responsible for problem solving and judgment and motor function.
• The parietal lobesmanage sensation, handwriting, and body position.
• The temporal lobesare involved with memory and hearing.
• The occipital lobescontain the brain’s visual processing system.

The human brain is surrounded by a layer of tissue called the meninges. The skull (cranium) helps protect the brain from injury.

The most common problems in Human Brain

Headache:There are many types of headaches; some can be serious but most are not and are generally treated with analgesics/painkillers.

Stroke (brain infarction):Blood flow and oxygen are suddenly interrupted to an area of brain tissue, which then dies. A blood clot, or bleeding in the brain, are the cause of most strokes.

Intracerebral haemorrhage:Any bleeding inside the brain.

Concussion:A brain injury that causes a temporary disturbance in brain function. Traumatic head injuries cause most concussions.

Cerebral oedema:Swelling of the brain tissue in response to injury or electrolyte imbalances.

Brain tumour:Any abnormal tissue growth inside the brain. Whether malignant (cancer) or benign, brain tumours usually cause problems by the pressure they exert on the normal brain.

Hydrocephalus:An abnormally increased amount of cerebrospinal (brain) fluid inside the skull. Usually this is because the fluid is not circulating properly.

Normal pressure hydrocephalus: A form of hydrocephalus that often causes problems walking, along with dementia and urinary incontinence. Pressures inside the brain remain normal, despite the increased fluid.

Meningitis:Inflammation of the lining around the brain or spinal cord, usually from infection. Stiff neck, neck pain, headache, fever, and sleepiness are common symptoms.

Encephalitis: Inflammation of the brain tissue, usually from infection with a virus. Fever, headache, and confusion are common symptoms.

Traumatic brain injury: Permanent brain damage from a traumatic head injury. Obvious mental impairment, or subtler personality and mood changes can occur.

Parkinson’s disease:Nerves in a central area of the brain degenerate slowly, causing problems with movement and coordination. A tremor of the hands is a common early sign.

Huntington’s disease: An inherited nerve disorder that affects the brain. Dementia and difficulty controlling movements (chorea) are its symptoms.

Epilepsy: The tendency to have seizures. Head injuries and strokes may cause epilepsy, but usually no cause is identified.

Dementia:A decline in cognitive function resulting from death or malfunction of nerve cells in the brain. Conditions in which nerves in the brain degenerate, as well as alcohol abuse and strokes, can cause dementia.

Alzheimer’s disease:For unclear reasons, nerves in certain brain areas degenerate, causing progressive dementia. Alzheimer’s disease is the most common form of dementia.

Theseexternal partsof human body are connected to the five major sense organs which tell us about our surroundings. All these parts are observable from outside, but they establish the connection between our internal part and external environment either mechanically or electrically.

The shape and size of the body parts differ from person to person. This makes us look different from one another. Thus, even in a crowded room, we can identify our friend easily. Men and women body parts are mostly alike, except for a few sexual differences. The following are main parts of ourbodyand some related components.

SKIN

Theskinis one of the most important parts of your body. It is also the largest organ of the body and helps the body in performing various different functions. One of the main functions of skin is that it provides a protective covering for the body and also protects all the organs inside. The skin, which is a semi-permeable membrane, allows nutrients to go inside, whereas it keeps all the undesirable things outside. It also helps in regulating temperature and excretion. Skin has three layers:

• The epidermis,the outermost layer of skin and the most resistant, provides a waterproof barrier and creates our skin tone.
• The dermis,beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands.
• The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.

The skin’s colour is created by special cells called melanocytes, which produce the pigmentmelanin. Melanocytes are located in the epidermis.

The most common Skin Conditions include:

Rash:Nearly any change in the skin’s appearance can be called a rash. Most rashes are from simple skin irritation; others result from medical conditions.

Dermatitis: A general term for inflammation of the skin. Atopic dermatitis (a type of eczema) is the most common form.

Eczema: Skin inflammation (dermatitis) causing an itchy rash. Most often, it’s due to an overactive immune system.

Dandruff:A scaly condition of the scalp may be caused by seborrheic dermatitis, psoriasis, or eczema.

Acne:The most common skin condition, acne affects over 85% of people at some time in life.

Warts:A virus infects the skin and causes the skin to grow excessively, creating a wart. Warts may be treated at home with chemicals, duct tape, or freezing, or removed by a physician.

Herpes: The herpes viruses HSV-1 and HSV-2 can cause periodic blisters or skin irritation around the lips or the genitals.

Shingles (herpes zoster):Caused by the chickenpox virus, shingles is a painful rash on one side of the body. A new adult vaccine can prevent shingles in most people.

Ringworm:A fungal skin infection (also called tinea). The characteristic rings it creates are not due to worms.

Some of these Skin conditions can be addressed using Treatments, including the following:

Antibiotics: Medicines that can kill the bacteria causing cellulitis and other skin infections.

Antifungal drugs:Topical creams can cure most fungal skin infections. Occasionally, oral medicines may be needed.

Skin moisturisers (emollients):Dry skin is more likely to become irritated and itchy. Moisturisers can reduce symptoms of many skin conditions.

Apart from the skin which covers all parts, the main parts of human body are: head, neck, trunk and limbs. Each part has different functions and contains different organs. Whether we are walking, talking, sleeping, playing or sitting, our body is constantly working hard to keep us in full health. It is important to know our body in order to take care of it and live a long healthy life.

HEAD

The human head is the upper extremity of the body, connected by the neck to the trunk. It has an oval shape and it hosts the brain. On the front part called face, the head contains four sense organs: nose, eyes, ears and mouth. They all send sensation messages to the brain: the nose sends smells, the eyes send images, the ears send sounds and the mouth sends tastes. The following are the main features of our head and their functions.

Hair:Our hair is not only found on the head, but all over the body. The only areas on the body where hairs are not present are the palms of the hands, soles and the lips. Even if you cannot see the body hair on some parts of your body, there are no human body parts where hairs are not really present. The colour of the hairs may be very light, so much so that they almost seem invisible. Hairs are rooted in the second layer of skin. They are made up of a special kind of protein known as keratin.

Eyes:The eyes are a significant part of the body anatomy. There are three different layers that make up the human eyes. These are known as the vascular, nervous, and the fibrous tunic. The outermost layer of the eyes is known as the fibrous tunic. This layer is composed of the cornea and the sclera, which is the outermost protective layer. The middle layer consists of the irises, the ciliary body, and the choroids. The innermost part of the eye consists of the retina.

Ears:Our ears are one of the five sensory organs and allow us to hear sounds. The ears collect the various sounds in the environment and transmit the auditory signals to the brain. The ear is made up of three main sections: –the outer ear or the auricle, the middle ear, and the inner ear. Apart from collecting sounds and transmitting the signals to the brain, the ears are also known to help maintain the body’s balance.

Nose:The nose is one of the main organs of the respiratory system. The respiratory system is responsible for bringing in the oxygen from the environment, utilising it, and expelling the carbon dioxide. The nose is also essential for discerning various smells. The nose performs the most important of the respiratory system functions and that is to inhale air.

Teeth:The teeth are important and help in the digestion of foods. It is our teeth that help us chew food, allowing the digestive enzymes in the saliva to mix with the food.

Tongue:Tongue is a strong muscle that performs a different function than the regular muscular system functions. The tongue is covered with taste buds that help us discern various tastes.

NECK

When you study the body anatomy and organs, the neck comes across as a load bearing organ that connects the head to the rest of the body. Our neck is also very important because it attaches the base of the skull to the shoulders and the spine runs through it. Among the other functions of body parts, the neck provides movement to the head. It also sustains the head and helps it move up and down, left and right. Another important function of the neck is protecting the nerves that send sensory and motor information from the brain to the rest of the body.

Theshouldersare another load bearing joints that give us the erect stature and also attach the arms to the body. The arms are attached into the shoulder sockets and their movements are possible because of the shoulders. Below the shoulders lies the chest, stomach, waist, back and hips, which are part of the trunk.

TRUNK

The trunk is the body part that connects all the other parts and hosts many important internal organs such as: heart, lungs, stomach, liver, kidneys and reproductive organs that we shall detail in the next section.

LIMBS (LEGS AND ARMS)

A human being has four limbs: two arms and two legs. These limbs are what make the human body mobile. The arms end into hands, which, with their opposable thumbs, allow us to perform complex actions. The arms are the upper limbs, connected to the trunk in the superior side, one on the left and one on the right. The arm consists of: shoulder, elbow, forearm, wrist, palm and fingers. With the help of our arms we can catch, hold and carry objects.

1. hand
2. thumb
3. index finger
4. middle finger
5. ring finger
6. little finger
7. nail
8. knuckle

The legs, with the knees and the feet, carry our weight and help inlocomotion. The legs are connected to the trunk in the inferior side. The leg consists of: hip, thigh, knee, ankle, foot and toes. With the help of our legs we can walk, run and jump. The legs sustain the entire weight of the body and carry it where it needs to go.