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Second: Movement in Man

The study is concrened with the movement in man as an example for mammals.

Looking for your hands while turning over these pages, or your legs while walking on
your way to school, you will find that the movement depends on three systems, skeletal
system which supports the movement of limbs, the muscular system for contraction and

relaxation of the muscles that move the limbs and the nervous system whichhhhh gives
the order to the muscles to contract and relax.
The Muscular system:

The muscular system is a group of body muscles by which different parts of body
can move.

The unit of structure of the muscular system is the muscle. The muscle consists of
a muscular tissue. These muscles enable man to perform mechanical movements and
transfer from one place to another and usually known as flesh. The number of muscles
in man is about 620 muscles or more.

Functions of muscles:
The muscles are characterized generally by being filamentous and have the ability of
contraction and relaxation.

Muscle contraction is important to perform the following functions:

a) Movement, and includes the change in the position of certain organ in relation to
other parts of the body.

b) Transportation from one place to another.
c) Continuous movement of blood inside the blood vessels and to maintain normal

blood pressure inside blood vessels through the contraction of the smooth muscles
“involuntary” in the wall of blood vessels.

d) Maintain body posture either in sitting or standing postions especially by the muscles
of neck, trunk and lower limbs.

Structure of the skeletal muscle:

The skeletal muscle consists of a large number of thin filaments called muscle cells or muscle
fibres. Each muscle fibre consists of a group of myofibrils, 1000 to 2000 in number, arranged

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