Muscles and Muscle Tissue

Active Lecture Questions

C H A P T E R

Copyright © 2010 Pearson Education, Inc.

9

Muscles and Muscle Tissue


Muscle cells are referred to as ________.

a. muscle fibers

b. muscle spindles

c. muscle myosin

d. muscle actin


Which of the following is not a prefix used to refer to muscle?

a. Mys

b. Myo

c. Sarco

d. Lemma


Of the following muscle types, which is the only one subject to conscious control?

a. Smooth

b. Skeletal

c. Cardiac

d. All of these muscle types are subject to conscious control.


Which two types of muscle appear striated when examined under a microscope?

a. Smooth and skeletal

b. Smooth and cardiac

c. Cardiac and skeletal

d. Skeletal muscle is the only striated muscle type.


Which of the following muscular functions serves a metabolic function?

a. Movement

b. Posture maintenance

c. Joint stabilization

d. Heat generation


In order to receive a signal to contract, each skeletal muscle must be served by a(n) ________.

a. artery

b. nerve

c. vein

d. ligament


The elastic components of muscle consist of which elements?

a. Tendon, epimysium, muscle fiber

b. Bone, perimysium, blood vessel

c. Fascicle, bone, blood vessel

d. Tendon, epimysium, perimysium, endomysium


Which of the following components accounts for the bulk of muscle fiber volume (up to 80%)?

a. Glycosomes

b. Mitochondria

c. Myofibrils

d. Sarcoplasm


The functional unit of a muscle fiber is the __________.

a. sarcomere

b. myofibril

c. fascicle

d. myofilament


Which portion of a myosin molecule would be the most severely affected upon exposure to an enzyme inhibitor?

a. Tail

b. Hinge region

c. Head

d. The actin molecule


The thin filaments are not comprised of which of the following components?

a. Actin

b. Titin

c. Troponin

d. Tropomyosin


What is the major function of the sarcoplasmic reticulum?

a. Store sodium ions

b. Expel sodium ions from the cell

c. Expel calcium ions from the cell

d. Store calcium ions


What would happen to intracellular calcium levels if a muscle fiber were treated with a calcium channel–blocking drug?

a. Intracellular calcium levels would increase.

b. Intracellular calcium levels would decrease.

c. Intracellular calcium levels would be unchanged.

d. The muscle fiber would shrink.


What is the significance of the muscle fiber triad relationship?

a. The terminal cisternae subdivide the sarcolemma.

b. The T tubules bring calcium to the sarcoplasmic reticulum.

c. The sarcoplasmic reticulum transfers calcium to the T tubules.

d. The T tubules conduct electrical impulses that stimulate calcium release from the sarcoplasmic reticulum.


During a muscle contraction, the sliding filament theory would be apparent in a sarcomere because __________.

a. the I bands get longer

b. the A bands get shorter

c. the H zone becomes less obvious and the Z discs move closer together

d. the Z discs get pulled closer to the I bands and the H zone becomes more obvious


At the neuromuscular junction, the muscle contraction initiation event is ______.

a. a release of calcium ions from the sarcoplasmic reticulum

b. conduction of an electrical impulse down the T tubules

c. binding of acetylcholine to membrane receptors on the sarcolemma

d. sliding of actin and myosin filaments past each other


What would be the response of a muscle fiber treated with an acetylcholinesterase inhibitor?

a. There would be a continued muscle fiber contraction in the absence of additional nervous system stimulation.

b. The muscle fiber would be nonresponsive to acetylcholine.

c. Acetylcholine would be retained in the axon ending.

d. The muscle fiber would contract then relax for a prolonged period of time.


In a muscle fiber, the key intracellular event that stimulates muscle contraction is known as ________.

a. polarization

b. depolarization

c. repolarization

d. potential


During depolarization, the sarcolemma is most permeable to _______.

a. sodium ions

b. potassium ions

c. calcium ions

d. chloride ions


The time period between action potential initiation and mechanical activity of a muscle fiber is called the _________.

a. latent period

b. refractory period

c. action potential

d. excitation period


What is calcium’s function during muscle contraction?

a. Calcium binds to troponin, changing its shape and removing the blocking action of tropomyosin.

b. Calcium binds to troponin to prevent myosin from attaching to actin.

c. Calcium depolarizes the muscle fiber.

d. Calcium flows down the T tubules to stimulate the influx of sodium from the sarcoplasmic reticulum.


Corpses usually exhibit rigor mortis because __________.

a. ATP hydrolysis is stimulating myosin head attachment to actin

b. a lack of ATP hydrolysis prevents myosin head detachment from actin

c. calcium stores become deficient

d. sodium stores become deficient


Small precise movements are controlled by ______ motor units.

a. small

b. large

c. many

d. few


A muscle contraction increases in strength up to a point because ________.

a. stronger stimuli inhibit motor unit activation

b. recruitment occurs and more motor units respond to stronger stimuli

c. more calcium is available in the sarcoplasm

d. additional neurons begin stimulating each muscle fiber


Isometric contractions come into play when an individual is ________.

a. jumping

b. walking uphill

c. lifting a heavy object

d. maintaining an upright posture


A sprinter is more likely to depend on _______ respiration to generate ATP, whereas a Tour de France cyclist is more likely to rely on __________ respiration.

a. anaerobic; aerobic

b. aerobic; anaerobic

c. aerobic; aerobic

d. anaerobic; anaerobic


Sprinters typically possess more ________ muscle fibers.

a. slow glycolytic

b. fast glycolytic

c. slow oxidative

d. fast oxidative


A major difference between smooth muscle fibers and skeletal muscle fibers in terms of calcium influx is that ______.

a. smooth muscle fibers have a sarcoplasmic reticulum

b. calcium ions are stored in the sarcoplasm of smooth muscle

c. calcium ion influx occurs mostly from the extracellular fluid in smooth muscle

d. smooth muscle contraction does not involve calcium


A major cellular feature in smooth muscle that contributes to its rhythmicity and ability to participate in peristalsis is the presence of _________.

a. troponin complex

b. gap junctions

c. varicosities

d. caveolae


The principal neurotransmitter of skeletal muscle is acetylcholine. The major neurotransmitter(s) of smooth muscle is (are) _______.

a. acetylcholine

b. epinephrine

c. norepinephrine

d. all of the above

Muscles and Muscle Tissue

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