9-3. Exercise and Muscle Disease

Question 1

aerobic exercise

Answer 1

endurance exercise - moderately weak but sustained muscle activity, resulting in increase blood flow to muscle and more mitochondria within fibers

Question 2

What are the benefits of aerobic exercise?

Answer 2

more efficient muscle metabolism and greater endurance
overall metabolism
GI motility
neuromusclar coordination
cardiovascular function
respitory function

Question 3

anaerobic exercise

Answer 3

resistance training - muscles are pitted against high resistance, as in weight lifting or isometric exercise. Strength, not stamina, is important

Question 4

hypertrophy

Answer 4

increase in size of muscles due to increase in size of muscle fibers

Question 5

cross training

Answer 5

alternating aerobic activities with anaerobic ones providing the best program for optimal health

guidelines include:

1. stretching or warming up beforehand
2. heavy workout day followed by rest or an easy workout to allow muscles to recover and repair

Question 6

Overload Principle

Answer 6

forcing a muscle to work hard causes increased strength and endurance, but once the muscle adapts to the increased demands, it must be overloaded to produce further gains

Question 7

atrophy

Answer 7

degeneraiton and loss of muscle mass as individual fibers decrease in size (due to loss of myofibrils). No decrease in the number of muscle cells

Question 8

disuse atrophy

Answer 8

muscles that are not used begin to shrink (eg. bedrest, cast) - reversible with exercise

Question 9

denervation atrophy

Answer 9

if nerve supply to muscle is cut, it undergoes complete atrophy to 1/4 its original size

Question 10

myasthenia gravis

Answer 10

an autoimmune disorder in which the person makes antibodies that bind to receptor sites for ACh on sarcolemma. Prevents ACh from attaching and results in defective neuromuscular junctions, muscles have difficulty contracting

Question 11

myasthenia gravis is more common in ___

Answer 11

women between ages 20 - 50

Question 12

what are the symptoms of myasthenia gravis?

Answer 12

moves from small to large motor units:

early: weak eye muscles (double vision and droopy eyelids), difficulty swallowing, chewing and talking
later: limb muscles may become paralyzed, fatal if respitory muscles become paralyzed (rare)

Question 13

what are the treatments for myasthenia gravis?

Answer 13

anticholinesterase drugs that allow ACh to build up to high levels, predinose to reduce antibody levels

Question 14

muscular dystrophy

Answer 14

due to genetic defect, skeletal muscle fibers degenerate and fat is deposited instead. causes a weakening on both sides of the body.

Question 15

muscular dystrophy may be caused by a lack of ___

Answer 15

dystrophin - protein found in the sarcolemma of normal muscle fibers linking thin filaments to sarcolemma

Question 16

muscular dystrophy is more common in ___

Answer 16

boys, appearing between ages 3 to 5