All living things on earth-plants, animals and hu8man beings are made up cells. Our entire body –bones contain more cells. The smallest cells are the real blood cells. 50, 00, 000 of them would fit insides a drop of blood of the size of the letter `a’.

Our body has four parathyroid glands. Each is about the size of a rice grain. Their hormones enable the teeth and bones to make use of calcium. It is also necessary for proper functioning of the nervous system.

Human body contains 6 liters of blood. Of this 4 1/2 liters circulate and transmit nutritive fluids to body cells. The remaining blood is stored and reserved in the body and come in use during hemorrhage or whenever body required additional blood.

Kidneys clean the blood. Each day the heart is deliver150 liters of fluid to the kidneys. This fluid contains about 1kg of salt (sodium chloride), 500 gm of sodium bicarbonate, 250 gm of glucose and small quantities of others substances. They fitter out these waste matter and strain off any water is that the body does not need.

The heart is actually a powerful muscular organ in our body. It is made up of strong cardiac muscles. It constantly pumps blood to different parts of the body through veins, capillaries and arteries so that each cell gets the food and oxygen it needs.

We grow by about 8mm every night when asleep, but shrink to our farmer height on the next day.

Body parts

• Lower part of the brain controls hunger. The head of brain controls all the functions of the body. The human brain cells made up of neurons or nerve cells. Each neuron has a cell body with long never fibers. These fibers make minute connections which carry the impulses to the brain and back to the organs.
• There are 27 bones on a human hand
• Skin the largest organ of the body
• Enzymes regular the chemical actions in the human body
• A person can lose as much as one-third of all the blood in his body and still live
• The brain, the most important organ is protected by the skull. 22 bones make up the skull. The beautiful face covers it.
• The human body has 600 muscles and 206 bones. They provide the shape to the body and make all the physical movements.
• The human body produces energy by burning carbohydrates and fats inside its cells. This process is called Oxidation. Oxygen needed for oxidation is got from air through respiration.