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Muscular System. Victoria Emi Jorge Jonathan. Muscular System Facts. . There are over 600 muscles that make up the muscular system . Muscles are bundles of fiber held together by connective tissue . There are 3 main kinds of muscle, Cardiac, Visceral, and Skeletal .
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Muscular System Victoria Emi Jorge Jonathan
Muscular System Facts • . There are over 600 muscles that make up the muscular system • . Muscles are bundles of fiber held together by connective tissue • . There are 3 main kinds of muscle, Cardiac, Visceral, and Skeletal
Cardiac muscle: forms the walls of the heart and contracts to circulate blood • Visceral muscle contracts to cause movement in these organs. • Visceral (smooth) muscle is found in the internal organs of the body such as those of the digestive and respiratory systems, and the blood vessels and eyes. • Cardiac and Visceral muscle are involuntary, meaning they function without conscious thought or control. • Skeletal muscle is attached to bones and causes body movement • Skeletal muscle is voluntary because a person controls its action.
Properties & Characteristics • Excitability-irritability, the ability to respond a stimulus such as nerve impulse • Extensibility- the ability to be stretched • Elasticity- allows the muscle to return to its original shape after it has contracted or stretched • Contractibility- muscle fibers that are stimulated by nerves contact, or become short and thick, which causes • movement
Action and Movement • Adduction- moving a body part toward the midline • Abduction- moving a body part away from the midline • Flexion- decreasing the angle between two bones, or bending a body part • Rotation- turning a body part around its own axis; for example, turning the head from side to side • Extension-Increasing the angle between two bones, or straightening a body part
Skeletal muscles attach to bones in different ways such as tendons and by fascia. • Tendons: are strong tough connective tissue cords • Fascia: is a tough sheet like membrane that covers and protects the tissue. • An Origin is when a muscle attaches to a bone and the end does not move. • The end that does move when the muscle contracts is called the Insertion. • Muscles are partially contracted at all times, even when we don’t use them. • They are always in a state of muscle tone (state of readiness to act)
It’s important to continuously use our muscles because lack of muscle tone can give as paralysis. • Our muscles can shrink in size and lose strength with lack of muscle use, you can also develop contracture, a painful severe tightening of a flexor muscle resulting in bending of a joint.