Anatomy Quiz 9

Which figure exhibits concentric contraction of the biceps brachii muscle? A B C none of these choices

A

In the diagram, a tendon is formed by the merging of the following structures C, D, and H D and E H and C C and D All of these choices are correct.

C, D, and H

Increasing the number of active motor units within a skeletal muscle is called A. wave summation. B. fused tetanus. C. motor unit recruitment D. muscle tone. E. flaccidity.

C. motor unit recruitment.

Release of calcium from these structures triggers skeletal muscle contraction. A. myofibrils B. mitochondria C. terminal cisterns of sarcoplasmic reticulum D. T-tubules E. none of the answer choices

C. terminal cisterns of sarcoplasmic reticulum

On the diagram, where is the outer most layer of connective tissue encircling the entire muscle A B C D E

D

Which area of the myogram shows a sustained contraction where individual twitches are indiscernible? A B C D none of these choices

D

What energizes the myosin head? A. the actin filaments B. calcium ions C. potassium ions D. ATP hydrolysis reaction E. ADP synthesis

D. ATP hydrolysis reaction

In the diagram, which structure helps return a stretched sarcomere to its resting length? B C E Both B and C All of these choices are correct.

E

In the diagram, what is the basic functional unit of a myofibril? B C F Both B and C All of these choices are correct.

F

In the diagram, where would you find stored Ca2+? B D G F K

F- SR

During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the Z disc. H zone. M line. A band. I band.

M line

Which of the following regions of the sarcomere contain thick filaments? zone of overlap A band H zone both A band and H zone all of these answer choices are correct.

all of these answer choices are correct

Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? sarcolemma, axon of neuron, T tubules T tubules, sarcolemma, myofilament muscle fiber, axon of neuron, myofibrils axon of neuron, sarcolemma, T tubules myofibrils, myofilaments, mitochondria

axon of neuron, sarcolemma, T tubules

Skeletal muscle contraction will continue to occur as long as the following chemicals are available in the cytosol of the muscle fiber. ATP and acetylcholine (ACh) calcium ions and ATP ACh and potassium ions sodium ions and ATP calciumand ACh

calcium ions and ATP

This is the outermost layer of connective tissue surrounding a skeletal muscle. tendon ligament endomysium epimysium perimysium

epimysium

In an isometric contraction the muscle develops tension but does not lengthen. widen does not expend energy conduct electrical current. exhibit elasticity.

lengthen.

Cross bridges are formed during muscle contraction when _____ on the thick filaments binds to _____ on the thin filaments. myosin; troponin myosin; troponin myosin; actin actin; myosin actin; tropomyosin

myosin; actin

This is the least powerful type of skeletal muscle fiber. slow oxidative fiber fast oxidative fiber fast glycolytic fiber slow glycolytic fiber none of these choices.

slow oxidative fiber

To stimulate skeletal muscle contraction, acetylcholine must cross the _____ of the neuromuscular junction and bind to receptors on the motor endplate. node of Ranvier synaptic cleft sarcolemma synapticend bulb transverse tubule

synaptic cleft

What regulatory proteins can be found in the thin filaments of skeletal muscle fibers? troponin and titin tropomyosin and troponin myosin and titin titin and tropomyosin tropomyosin and myosin

tropomyosin and troponin