Clinical Applications for Exam 3

A- = without, -trophy = nourishment
A wasting away of muscles where individual muscle fibers decrease in size because of progressive loss of myofibrils which is the opposite of muscular hypertrophy where there is an increase in the diameter of muscle fibers due to increased production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles. It results from very forceful, repetitive muscular activity, such as strength training.

Atrophy that occurs because muscles are not used . Bedridden individuals and people with casts experience disuse atrophy because the flow of nerve impulses to inactive skeletal muscle is greatly reduced.

The nerve supply to a muscle is disrupted or cut. Over a period of 6 months to 2 years, the muscle shrinks to about 1/4 its original size, and the muscle fibers are irreversibly replaced by fibrous connective tissue.

Damage like torn sarcolemmas in some muscle fibers, damaged myofibrils, and disrupted Z discs that comes from intense exercise as revealed from micrographs of muscle tissue taken from athletes before and after exercise. Microscopic muscle damage after exercise also is indicated by increases in blood levels of proteins, such as myoglobin and the enzyme creatine kinase, that are normally confined within muscle fibers.

.When skeletal muscles often become sore from 12 to 48 hours after a period of strenuous exercise. It is accompanied by stiffness, tenderness, and swelling. Although the cause of DOMS isn't completely understood, microscopic muscle damage appears to be a major factor. In response , muscle fibers undergo repair: New regions of sarcolemma are formed to replace tom sarcolemma and more muscle proteins are synthesized int eh sarcoplasm of the muscle fibers.

.After death, cellular membranes become leaky. Calcium ions leak out of the sarcoplasmic reticulum into the cytosol and allow myosin heads to bind to actin . ATP synthesis ceases shortly after breathing stops, however, so the crossbridges cannot detach from actin. The resulting condition, is rigor mortis, in which muscles are in a state of rigidity.

.electro- = electricity; myo- = muscle; -graph = to write
A test that measures the electrical activity in resting and contracting muscles. Normally, resting muscle produces no electrical activity; a slight contraction produces some electrical activity; and a more forceful contraction produces increased electrical activity.The test involves a ground electrode and then a fine needle inserted into the muscles and attached by wires to a recording instrument

Creatine is both synthesized in the body and derived from foods such as milk, red meat, and some fish. Adults need to synthesize and ingest a total of about 2 grams of creatine daily to make up for the urinary loss of creatinine, the breakdown product of creatine. Some studies have demonstrated improved performance during explosive movements, such as sprinting. Other studies, however, have failed to find a performance-enhancing effect of creatine supplementation. Moreover, ingesting extra creatine decreases the body's own synthesis of creatine, and it is not known whether natural synthesis recovers after long-term creatine supplementation. In addition, creatine supplementation can cause dehydration and may cause kidney dysfunction. Further research is needed to determine both the long-term safety and the value of creatine supplementation.

.Regular, repeated activities such as jogging or aerobic dancing increase the supply of oxygen-rich blood available to skeletal muscles for aerobic cellular respiration. By contrast, activities such as weight lifting rely more on anaerobic production of ATP through glycolysis. Such anaerobic activities stimulate synthesis of muscle proteins and result, over time, in increased muscle size. Athletes who engage in anaerobic training should have a diet that includes an adequate amount of proteins allowing the body to synthesize muscle proteins and increase muscle mass. Aerobic training builds endurance for prolonged activities; in contrast, anaerobic training builds muscle strength for short-term feats.

Involves a workout regimen that incorporates both Aerobic training and strength training.

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Degeneration, atrophy, loss or reduction of tendon reflexes, and loss of muscle tone in muscles from a disruption in the balance of electrolytes or even certain disorders of the nervous system. .

.Hypo- = below; Hyper- = above
Hypotonia refers to a decreased or lost muscle tone (which is said to be flaccid), while Hypertonia refers to increased muscle tone (expressed in two ways; spasticity or rigidity)

Characterized by increased muscle tone (stiffness) associated with an increase in tendon reflexes and pathological reflexes

Refers to an increased muscle tone in which reflexes are not affected, as occurs in tetanus.