A&p Chapter 10 - Muscular Tissue

A single somatic motor neuron and all of the muscle fibers it stimulates is known as a                           .

The sequence of events resulting in skeletal muscle contraction are: a) generation of a nerve impulse; b) release of the neurotransmitter acetylcholine; c) generation of a muscle action potential; d) release of calcium ions from the sacroplasmic reticulum; e) calcium ion binding to troponin; f) power stroke with actin and myosin binding and release.

• True

• False

The synaptic end bulbs of somatic motor neurons contain synaptic vesicles filled with the neurotransmitter                             .

In muscle physiology, the latent period refers to:

• The period of lost excitability that occurs when two stimuli are applied immediately one after the other

• The brief contraction of a motor unit

• The period of elevated oxygen use after exercise

• An inability of a muscle to contract forcefully after prolonged activity

• A brief delay that occurs between application of a stimulus and the beginning of contraction

Which of the following are sources of ATP for muscle contraction? 1) creatine phosphate, 2) glycolysis, 3) anaerobic cellular respiration 4) aerobic cellular respiration, 5) acetylcholine

• 1,2, and 3

• 2,3, and 4

• 2,3 and 5

• 1,2,3, and 4

• 2,3,4, and 5

Which of the following muscle proteins and their descriptions are mismatched?

• Titin: regulatory protein that holds troponin in place

• Myosin: contractile motor protein

• Tropomyosin: regulatory protein that blocks myosin-binding sites

• Actin: contractile protein that contains myosin-binding sites

• Calsequestrin: calcium-binding protein

What would happen if ATP were suddenly unavailable after the sarcomere had begun to shorten?

• Nothing, the contraction would proceed normally

• The myosin heads would be unable to detach from actin

• Troponin would bind with the myosin heads

• Actin and myosin filaments would separate completely and be unable to recombine

• The myosin heads would detach completely from actin

During muscle contraction all of the following occur except

• Cross-bridges are formed when the energized myosin head attaches to actin's myosin-binding site

• ATP undergoes hydrolysis

• The thick filaments slide inward toward the M line

• Calcium concentration in the cytosol increases

• The Z discs are drawn toward each other

Which of the following is not true concerning sarcomeres (before contraction begins) and muscle fiber length-tension relationships?

• If sarcomeres are stretched, the tension in the fiber decreases

• If a muscle cell is stretched so that there is no overlap of the filaments, no tension is generated

• Extremely compressed sarcomeres result in less muscle tension

• Maximum tension occurs when the zone of overlap between a thick and thin filament extends from the edge of the H zone to one end of a thick filament

• If sarcomeres shorten, the tension in them increases

The wasting away of muscle due to lack of use is known as                         while the replacement of skeletal muscle fibers with scar tissue is known as                       .