Human Physiology

Lesson 15 : Muscular System


Muscles constitute largest organ of the body on weight basis. There are about 75 pairs of muscles involved in maintenance of body posture and movements. However, in total 650 voluntary muscles are present in body that contracts in voluntary fashion including body movements, eye ball movement, facial expression, speech, chewing, swallowing, eyelid movements etc. Other kinds of muscles showing involuntary movements (internal muscles) are present in heart, blood vessels, gastro-intestinal tract, urinary tract, reproductive tract and respiratory tract performs other specific functions of these organs.

Interesting features are:

  • The word ‘muscle’ arises from ‘musculus’, Latin meaning little mouse. As muscles bulged and rippled, people thought they looked like tiny mice under the skin.
  • The body has more than 640 skeletal muscles. They are by far the bulkiest parts of the body, making up about 40% of total weight.
  • The smallest muscle is the stapedius, located deep in the ear (2-3 mm).
  • The largest muscle is the gluteus maximus in the buttock. It pulls the thigh back when we run and jump.
Last modified: Tuesday, 10 April 2012, 6:43 AM