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Preksha Dhyana
are held together rigidly.
Muscles
Muscles can be called "machines of the body” transforming chemical energy into directed mechanical force and generally producing movement of the body as a whole, of body-parts and of various fluids through specific ehannels.
In a muscular system makes up 42 percent while in a woman 36 percent of the body weight. It consists of 620 muscles working together to move the 206 bones of the skeleton. A further 30 or so muscles are needed to ensure the passage of food though the intestines, to circulate the blood round the body and operate other internal organs.
There are three types of muscle tissue differing in structure, mode of action and functions : (i) Skeletal (or striated) muscles which are used for loco
motion. They are attached to bones. They contract rapidly and their contractions permit movement of arms, legs and other parts. They have a capacity for tremendous power but they cannot keep up their exer
tion long: after a short time they must rest. (ii) Smooth muscles which line the various organs and in
testine. They are slow and steady and can go on con
tracting day after day without resting. (iii) Cardiac Muscle (heart) is the special muscle that forms
the wall of the heart. They all operate in the same general way because they are specialized in one common property : contractility. They contract and they relax. The fibers which make up the muscles are able to shorten their length by 30 to 40 percent.
With very few exceptions (such as the blinking of the eye) single muscles never contract by themselves; rather whole sets of muscles contract together or in sequence or in opposition to achieve a variety of movement. Actions of Muscles
Skeletal muscles are firmly attached at each end to different bones. When a muscle contracts, a pull is exerted on both bones but one is stabilized by contractions of
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