Basic Type of Nutrition

Eating a balanced diet is an important part of good health. The food we eat supplies the nutrient required to build and repair the body, and to provide it with energy. Most of our nutrition consists of  three food types-Carbohydrates, proteins, and fats- but vitamin and minerals are also needed in tiny amounts. Water and dietary fibre are other key components. To remain healthy, a person should eat a variety of food in the correct proportion. Carbohydrates, the body's main source of energy, come in two forms- complex carbohydrates and sweet-tasting sugars.

FATS AND OILS

Rich in Fats and Oil 

Although fats and oils supply vitamins and are essential to the functioning of the body, they should be consumed in moderation. Plant oils, such as olive oil,contain unsaturated fatty acids(as do oily fish),which are good for health. However, saturated fatty acids, contained in many animals foods and added to processed foods, can clog arteries.

PROTEINS AND DAIRY FOODS

Rich in Protein and Dairy food

About 15 percent of our diet should include proteins needed for growth and repair.Foods rich in proteins include nuts, beans, eggs,fish, meat. Red meat is also rich in saturated fat, harmful to health if eaten in excess. Dairy foods, such as milk and cheese, supply the bone- building mineral calcium and some proteins, but can also be high in fats.

SUGARS

Rich in Sugar

Foods such as sweets, cakes, and biscuits should be eaten sparingly because they contain lots of added sugar. Eating large amount of sugar gives the body sudden bursts of energy rather than the constant stream it obtains from complex carbohydrates. Sugar that is excess to requirement is stored as fat, causing a person to put on weight.

FRUITS AND VEGETABLES

Rich in Vitamins and Minerals

Fruit is a good source of water, fibre and vitamins, and the natural sugars that give us a burst of energy. Many also supply antioxidants, which can reduce the risk of diseases. Vegetables contain vitamins and minerals and are a good source of fibre. Nutritionists recommend we eat at least five portion of fruit and vegetables daily.

COMPLEX CARBOHYDRATES

Rich in Carbohydrates

  Starch is the main complex carbohydrates in our diet. Foods rich in starch include pasta,cereals,potatoes,bread and rice. During digestion, starch is broken down to the sugar glucose, the body's main source of energy. Complex carbohydrates should make up about half of our diet.

SENSES

Our senses make aware of the world around us, and the changes that are happening in it. The eyes detect light waves, and the ears sound waves,enabling us to see and hear. The tongue and nose detect dissolved chemicals, so we can taste,smell,and enjoy flavours .The skin allows us too feel the texture and warmth of objects.

1. VISION 

Sense of vision

Vision is the most important sense, providing the brain with an immense amount of information about the body's surroundings. Light reflected from, or produced by, outside objects is automatically focused onto a layer of light receptors that lines the back of the eye . In response, these receptors send signals to areas at the back of the brain. from there, we can determine what we are looking at and where it is, thus enabling us to "see" moving, 3-D images in colour.

2. HEARING 

Sense of hearing

The ears detect waves of pressure, called sound waves, that travels through the air. Sound waves are produced by objects, such as ringing mobile phone or bell, which move or vibrate. the waves pass into the inner ear, which is enclosed in bone on the side of the skull.
Here, receptors convert pressure waves into signals. The signals travel to the brain, which identifies the pitch, volume,and direction of  the sound.

3. TASTE 

Sense of taste

Small projections on the tongue,called papillae,house taste  receptors called taste buds. Food molecules dissolved in saliva are detected by the taste buds. These can distinguish between five  basic tastes-sour,sweet,salty,bitter and umami(savoury and meaty).As well as helping us to enjoy food , our sense of taste enables us to detect foods that may be poisonous. 

4.TOUCH 

Sense of touch
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The skin acts like a sense organ. It contains several different types of receptors that enables us to "feel"our surroundings. most are touch receptors that send signals to the brain when the skin comes into contact with objects. some detect light touch, some heavier pressure,and some vibrations. Other receptors in the skin pick up temperatures changes or detect pain.

5.SMELL 

Sense of smell

The nose can detect more than 10,000 different smells. When air is breathed into the nose, odour molecules dissolve in watery mucus and are detected by odour receptors high in the roof of the nasal cavity. together, the senses of smell and taste enables us to detect flavours. Smell is more important, however, which explains why food lacks flavour when we have a blocked nose. Some smells, such as those produced by burning, can warm us of danger.

BRAIN

Safely inside the skull, the brain allows the sense ,think ,learn,remember,and move it. It also automatically regulates vital function such as breathing, the cerebrum, the main part of the brain ,has two halves, or hemispheres. The left hemisphere controls  the right side of the body and is in charge of language, maths, and problem  solving , while the right side controls the body's left side and deals with creativity, music, and art. The cerebrum's many tasks are carried out by it's outer layer , or cortex. This has distinct areas that have different roles. Motor areas trigger movement,sensory areas deal with the senses, while association areas interpret information.

1. PREFRONTAL CORTEX 

The most complex part of the cerebrum, the prefrontal cortex makes us what we are. It determines our personality and intellect , and enables us to reason, plan, create, and learn complex ideas, and have a conscience.

2. BROCA'S AREA 

Named after paul broca, the 19th century doctor who discovered it, Broca's area is normally found in the left hemisphere. It plans what a person wants to say and send instructions to muscle in the throat, tongue, and lips that produce speech.

3. PREMOTOR CORTEX

 Learned movement skills, such as playing tennis,are controlled and coordinated by the premotor cortex.It tells specific muscles, to contract either through the primary motors cortex or, in some cases, directly.

4.PRIMARY MOTOR CORTEX

Most movements we make are controlled by the primary motor cortex. Guided by information from the cerebellum and other brain parts,it sends instructions to muscles that move the skeleton instructing them when,and in what sequences, to contract.

5. PRIMARY  SENSORY CORTEX

Receptors in the skin for touch, pressure,vibration,heat and cold, and pain send signals to the primary sensory cortex enabling us to feel those sensations. Our lips and fingerprints have high concentrations of receptors, hence their sensitivity.

6. SENSORY ASSOCIATION CORTEX 

Basic information about touch, pressure, and other skin sensations is passed on by the primary sensory cortex to the sensory association cortex. Here sensations are analyzed,stored and compared with previous experiences,It enables us to identify objects by touch.

7.PRIMARY VISUAL CORTEX

When lights hits the retain at the back of each eye,its light detector sends signals to the primary visual cortex. Here those signals are interpreted as basic shapes, colours,and movements before being passed cortex.

8. VISUAL ASSOCIATION CORTEX 

This is where information from the primary visual cortex about seen is interpreted and compared with previous visual experiences. The visual association cortex identifies what we are look-ing at and where it is in space, enabling us to "see"it. 

9.CEREBELLUM 

The cerebellum is responsible for producing smooth, coordinated movements of the body. It analyzes incoming about the body's current position and movement , then interacts with the primary motor cortex to precisely time muscle contractions.

10.WERNICKE'S AREA 

Usually located in the left hemisphere, wernicke's area gives meaning to words that have been heard or read. Named after the German doctor Karl Wernicke, it has a direct link to broca's area enabling us to speak the words we hear or see.

11. PRIMARY AUDITORY CORTEX 

When sounds are detected by the two ears they send signals to the primary auditory cortex. Here the loudness, pitch (whether high or low), and rhythm of sounds are identified. that information is passed on to the auditory associations area.

12. AUDITORY ASSOCIATION AREA

Sounds are "heard" in the auditory association area. Using information received from the primary auditory cortex, it pieces together the complete sound.and.. by comparing it with sounds stored in memory, identifies it as, for example, music,speech, or thunder.

   

      

SKIN,HAIR,AND NAILS

Skin is the body's protective overcoat, forming a barrier between vulnerable body tissues and the harsh, changing condition of the outside world. It prevents water loss, blocks invasion by germs, repairs itself when damaged, helps us keep warm, and enables us to sense our surrounding. The uppermost layer of the skin is made from dead cells filled with a tough, waterproof substance called keratin. Hair and nails, both derived from skin,are also made from dead,keratin-filled cells.

1.SKIN CROSS-SECTION 

A section through the skin reveals that it has two parts. The epidermis is a germ-proof, waterproof barrier that protects against harmful rays in sunlight . the thicker dermis contains  blood vessels, sensory receptors,and sweat glands.

2. SWEAT 

This is salty liquid is produced by sweat glands in the demis. In hot conditions, sweat is released onto the skin's surface. It then evaporates, cooling the body and helping to maintain a constant body temperature of 37 degree celsius (98 degree farahnite).

3. SKIN COLOUR 

Special cells in the epidermis produce the brown pigment melanin, which filters out harmful ultraviolet rays from sunlight before they can damage skin cells.

4. FINGERNAIL 

Ideal for gripping objects and scratching itches, fingernails are clear plates that protects the sensitive upper parts of the fingertips.The cells that make nails die,flatten,and fill with keratin as they are pushed forwards from the nail's root.

 

5. HAIR 

Millions of hairs grow from the skin covering most body areas.Scalp hairs protect the skin from sunlight and reduce heat loss. Finer, shorter body hairs sense the presence of insects on the skin before they can sting or bite us.

6. TOUCH RECEPTORS 

The dermis contains a range of receptors that respond to soft touch, firmer pressure , and vibrations, and send signals to the brain so we can feel our surroundings.The dermis also has receptors that detect pain,heat,and cold.

BLOOD

Flowing all around your body , blood delivers food , oxygen , and other essentials to trillions of cells and remove their wastes . blood also distributes heat around your body and defends it against infection. blood is made up of a yellow liquid plasma in which blood cells float. red blood cells pick up oxygen in the lungs and deliver it to your body's cells. white blood cell can defend the body against disease causing germs. blood also contain platelets, which enable it to clot to seal damaged blood vessels. the heart pumps blood around the body along three types of blood vessels. arteries carry blood away from the heart, while veins return blood to the heart. microscopic capillaries link arteries and veins and supply blood to cells.

Circulating around the average body are 5 litres (8.8 pints) of blood.
Oxygen rich blood in arteries is bright red in colour oxygen poor blood in veins is dark purple red.
Blood is 55 % plasma and 45% blood cells.

One drop of blood contains 250 millions of red blood cells.375,000 white blood cells ,and 16 million platelets.
Oxygen carrying red blood cell make up 99% of all blood cells.
Every second,two million new red blood cells are made by jelly like red marrow inside bones.

During a lifespan of 120 days, A red blood cells travel around the body 170,000 times - once each minute. It is ten dismantled and recycled by the spleen and liver.
Packed into every red blood cells are 250 million red - coloured haemoglobin molecules.Each one carries four oxygen molecules, so a single red blood cell can transport one billion oxygen molecules.
Plasma is 90% water and contains more than 100 different dissolved substances including food,waste,hormones,and salts.

White blood cells called neutrophils and macrophages eat germs. Lymphocyte white blood cells disable germs by releasing chemicals called antibodies.
Unravelled and stretched out, one adult's blood vessels would encircle earth twice. Capillaries would make up 98% of the total length.
Each as broad as  a thumb , the largest artery and vein (the aorta and vena cava) are 2,500 times wider than a capillary, which is just one - tenth the width of a hair.
The heart is made largely of cardiac muscle, which does not tire.

Over a lifetime of 70 years, the heart beats 2.5 billion times without taking a rest.
 The heart beats, on average, 70 times a minute. Heart rate can double or triple during exercise to get extra oxygen to your muscles.
Each person belongs to one of four blood groups-A,B,AB,or O . Blood groups are determined by tiny "markers" carried by red blood cells.
 

RESPIRATION

The body's trillion of cells require an uninterrupted supply of oxygen to release the energy they need to stay alive . They get this name by means of a process called respiration . Air containing oxygen is breathed into the body by the respiratory system. Oxygen enters the blood stream through the lungs and carried to body cells . waste carbon dioxide is carried by the blood to the lungs breathed in. 

RESPIRATORY SYSTEM 

Located in the head , neck, and chest , the respiratory system consists of the lungs , which fill most of the chest , and the air passages - nasal cavity , throat , larynx , trachea , and bronchi - that carry air . this x-ray shows the parts of the respiratory system located in the chest .

1. TRACHEA 

 

Also called the windpipe, this flexible tube carries air between the larynx (voice box) at the base of the throat and the two bronchi that arise at its lower end . up to 20 C shaped rings of cartilage that encircle the trachea hold it open when you breathe in . mucus lining the trachea cleans the incoming air by trapping dirt and germs , a process that began in the nasal cavity .
 

2. BRONCHIAL TREE 

Once inside a lung , each bronchus divides into smaller bronchi that then spilt even further . these , in turn , divide repeatedly to form smaller branches called bronchioles . this arrangement is often called "the bronchial tree" because its structure looks like an upside down tree with the trachea as the trunk , bronchi as branches , and bronchioles as twigs . 

3. BRONCHIOLES  AND ALVEOLI 

The narrowest bronchioles end in 300 million air filled bags called alveoli that fill most of the lungs and are surrounded by blood capillaries . oxygen passes through the wall of each alveolus into the bloodstream in exchange for carbon dioxide , which moves in the opposite direction . the alveoli provide a large surface across which this exchange take place efficiently . 

4. DIAPHRAGM 

 

Situated just below the lungs, the diaphragm plays a key role in breathing . when breathing in, the diaphragm contracts and flattens as muscles pull the ribs upwards and outwards . this increases the space in the chest so that air is sucked into the lungs . when breathing out the relaxed diaphragm is pushed upwards , and the ribs move downwards and inwards , squeezing air from the lungs .  

IMPORTANT POINTS 

The trachea carries air to and from the lungs .
Twelve  pairs of ribs form the ribcage , which protects the lungs and aids breathing
The right bronchus branches from the trachea and divides repeatedly inside the right lung
Muscles between the ribs move the ribcage , which help to pull air into the lungs .
Branches o the smallest bronchioles reach the deepest parts of the lung
The diaphragm is a domed sheet of music that separates chest from abdomen . 

BODY SYSTEMS

BODY SYSTEMS 

The body's trillions of cells are highly organised .Cells of the same type are grouped together in tissues. Two or more types of tissues are used to build organs that perform specific role. Linked organs from different system that each carry out an essential job, such as digestion. There are 12 body systems that cooperate and interact with each other to form the human body. The organs six systems are the integumental  (skin), skeletal(bones) , muscular , endocrine (hormones) ,immune (defence), and reproductive system.

BRAIN

 The brain is the centre of the nervous system, which is responsible for controlling body activities . It is dominated by the folded cerebrum that enables us to feel,think and remember , and instructs the body to move. Other brain parts are the cerebellum, tucked under the cerebrum, and the brain stem , which automatically controls breathing and heart rate and links the brain to the spinal cord.

SPINAL CORD 

An extension of the brain that runs down the back , the spinal cord relays signals between brain and body through the spinal nerves connected to it . It also controls many of the body's automatic reflex action ,such as pulling  the hand back if it touches something sharp. together the brain , spinal cord , nervous form the nervous system . 

HEART 

 The cardiovascular system moves blood around the body to deliver oxygen and food to all the body's cells , and to remove their wastes.located between the lungs , the heart is the centre of this system - a hollow , muscular pump that contracts without tiring more than 70 times a minute to force the blood around the body along blood vessels.

SPLEEN 

The spleen is part of the lymphatic system , the body's drainage network . it contains white blood cells , which fight infection by destroying bacteria , and also removes worn - out red blood cells from the blood . 

LUNGS 

The respiratory system consists of two lungs and the air passes that carry air from the outside . each lungs contain a network of branching tubes that end in millions of tiny air bags. it is from these bags that oxygen in the air passes into the bloodstream. it is carried to all body cells where it is used to release life giving energy from food .

LIVER 

The largest internal organ , the liver controls the composition of the blood , processing nutrients newly absorbed from the small intestine .

PANCREAS 

The pancreas releases chemicals called enzymes into the small intestine to aid digestion , and hormones(chemical messengers) into the blood to control level of glucose -the body's main fuel in the blood. 

STOMACH 

This muscular expands as it receives and stores food that has been chewed and swallowed . during storage the stomach's walls churn food into a part-digested "soup", which is released into the small intestine . 

DIGESTIVE SYSTEM 

 

The body needs nutrients for energy , growth , and repair . the digestive system breaks down food to release these essential nutrients . the system consists of the mouth and teeth , the oesophagus(a muscular tube leading from the mouth to the stomach), the stomach , and the small and large intestines . food is digested using mechanical force, such as chewing , and through chemical digesters called enzymes. nutrients are then absorbed into the blood and carried to the body's cells .

The large intestine turns waste into faeces (poo) and pushes them out of the body . 

The small intestine is a long  tube in which most digestion and absorption occurs .

URINARY SYSTEM 

Consisting of the kidneys , ureters , bladder , and urethra , the urinary system makes urine and removes it from the body . the kidneys make urine by removing wastes and excess water and salts from the blood thereby keeping its composition constant . Urine is stored in the bladder and expelled through the urethra at its base.