Page 9 - 8.5 MUSCLES
P. 9
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Working of muscles
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W o r k i n g o f mu sc l e s
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• •The contraction and relaxation of
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the muscles attached to the bones
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h h h e l p i n t h e mo v e me n t o f t h e b o n e s .
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help in the movement of the bones.
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• •When muscle contracts, it
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shortens and pulls the bone due to
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which the bone move at that joint.
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A A A mu s c l e c a n o n l y p u l l a b o n e i t
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A muscle can only pull a bone it
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cannot push a bone. The muscles
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joined to our bones work in pairs.
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W h e n o n e mu s c l e o f a p a i r
When one muscle of a pair
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contracts, then the other muscle of
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a p a i r i s r e l a x e d . A c o n t r a c t e d
a pair is relaxed. A contracted
mu s c l e c a n c o me b a c k t o i t s
muscle can come back to its
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o o o r i g i n a l p o s i t i o n o n l y w h e n t h e
original position only when the
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other muscle of the pair pulls it by
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contracting itself.
c o n t r a c t i n g i t s e l f .
