mechanisms of contractions

Question 1

A skeletal muscle fiber remains at rest until

Answer 1

stimulated by a motor neuron

Question 2

Neuromuscular junction

Answer 2

motor neurons connect to the sarcolemma at the motor endplate

Question 3

Neuromuscular junction is a synapse where

Answer 3

neurotransmitter molecules transmit signals

Question 4

Acetylcholine

Answer 4

the neurotransmitter released into the synaptic cleft that diffuses across the gap, stimulates the receptors, and initiates an impulse in the sarcolemma

Question 5

Nerve impulse travels over the sarcolemma and inward along the T tubules, which triggers

Answer 5

the release of calcium ions (Ca++)(SR)

Question 6

• Ca++ binds to troponin, which causes tropomyosin to

Answer 6

shift and expose active sites on actin

Question 7

ACh=

Answer 7

Acetylcholine

Question 8

Hydrolysis of adenosine triphosphate (ATP) yields the energy required for

Answer 8

muscular contraction

Question 9

ATP binds to the myosin head and transfers its energy there to perform the work of

Answer 9

pulling the thin filament during contraction

Question 10

Muscle fibers continually resynthesized ATP from the

Answer 10

breakdown of creatine phosphate

Question 11

Catabolism by muscle fibers requires

Answer 11

glucose and oxygen (O2)

Question 12

At rest, excess O2 in the sarcoplasm is

Answer 12

bound to myoglobin

Question 13

Red fibers(slow)

Answer 13

muscle fibers with high levels of myoglobin (used for long term work like running miles)

Question 14

White fibers (fast)

Answer 14

muscle fibers with little myoglobin (short and fast term like 200m dash)