Saturday 7 March 2015

HUMAN BODY AND ITS FUNCTIONING-7

THE MUSCULAR SYSTEM
All over our body are a number of muscles. As children we used to show off our strength, by bending the elbow, when the muscle gets shortened in length and bulges out.  Even when we stand up, a number of muscles are at work. That is why we get tired, after some time. When we walk, the muscles of the legs are very active.
Each muscle is attached to a bone. By contracting and then enlarging, the bones are made to move.  Tendons are the threads that bind the muscle to the bone.  Sawing wood by the old method, by using the big saw, creates musclemen, whose body may not have any fat layer. In my childhood, I have seen such giants , who are the envy of any woman! They eat one kilo of rice at a time. Boxers are the modern type.
Muscles of the intestine work to push the food forward. Eye lids open and close, by muscular action. Of course, the heart has strong muscles, which work  throught our life
BONES
Remove the muscles and then we see the skeleton, which is a collection of a number of individual pieces. Some are long and some very short as in the vertebral column. The latter is hollow in the centre. A thick cable of nerves pass through thus tunnel, called the medulla oblongata. Cut it and death is quick. That is why we hang the culprits or the lovers end their lives, by wringing ht neck. Every day, millions of fowl are killed this way. The bones are hollow and supplied by blood vessels. The pith inside produce blood corpuscles.
The bones are made of calcium and phosphorus. Decay of cells of the bone is called osteoporosis. In old age, bones crash easily because of decay. Milk and eggs are necessary in old age too.

Two bones are joined at many places. To avoid friction, cartilage tissue is placed between bones

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