Aerobic oxygen requiring metabolism After 30 to 40 seconds the supply of ATP

Aerobic oxygen requiring metabolism after 30 to 40

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Aerobic (oxygen-requiring) metabolism . After 30 to 40 seconds, the supply of ATP from glycolysis is depleted, and continued muscle activity relies on ATP production by aerobic respiration. In the presence of oxygen, pyruvic acid (formed from glycolysis) enters the mitochondria and is broken down completely to CO2 , H2O, and ATP. Aerobic metabolism generates large amounts of ATP compared with glycolysis. The mitochondria receive their supply of oxygen from two sources: the blood (oxyhemoglobin) and myoglobin. Myoglobin is an oxygen-carrying protein found in the muscle fibers. Muscle Terms The terms origin and insertion refer to the sites of muscle attachment. Most muscles cross or span at least one joint. When muscle contracts, one bone remains relatively stationary or immovable. The origin of the muscle attaches to the stationary bone, whereas the insertion attaches to the more movable bone. For example , the origin of the biceps brachii is the scapula, and the insertion is on the radius. On contraction of the biceps brachii, the radius (insertion) is pulled toward the scapula (origin). Prime Mover, Synergist, and Antagonist Although most movement is accomplished through the cooperation of groups of muscles, a single muscle is generally responsible foremost of the movement. The “chief muscle” is called the prime mover . Assisting the prime mover are “helper muscles” called synergists . Synergists are said to work with other muscles. In contrast, antagonists are muscles that oppose the action of another muscle. Muscle overuse and underuse terms Hypertrophy- Overused muscles increase in size. This response to overuse is called hypertrophy. Athletes intentionally cause their muscles to hypertrophy. Atrophy -If muscles are not used, they will waste away, or decrease in size. A person with a broken leg in a cast, for example, is unable to exercise that leg for several months. This lack of exercise causes the muscles of the leg to atrophy, which is called disuse atrophy.. Muscle atrophy can also develop when the nerves to the muscle are severed,
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which is called denervation atrophy. Finally, muscle atrophy is part of the normal aging process; this is called senile atrophy. Contracture- If a muscle is immobilized for a prolonged period, it may develop a contracture, an abnormal formation of fibrous tissue within the muscle. How Skeletal Muscle are Named Size - These terms indicate size: vastus (huge), maximus (large), longus (long), minimus (small), and brevis (short) Shape- Various shapes are included in muscle names, such as deltoid (triangular), latissimus (wide), trapezius (trapezoid), rhomboideus (rhomboid), and teres (round). Orientation of Fibers - Fibers are oriented, or lined up, in several directions: rectus (straight), oblique (diagonal), transverse (across), and circularis(circular). Location -The names of muscles often reflect their location in the body, such as pectoralis (chest), gluteus (buttock), brachii (arm), supra (above), infra (below), sub (underneath), and lateralis (lateral).
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  • Fall '19
  • muscle weakness, muscle atrophy, functions of muscles

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