Week Four Quiz
Chapter 9 Muscular System: Histology and Physiology________________________________________

1. Which of the following is NOT a function of skeletal muscle?
a. body movement

b. maintenance of posture

c. respiration

d. constriction of organs

e. production of heat
2. Which of the following is true?
a. Skeletal muscle is capable of spontaneous contraction.

b. Smooth muscle is found in the walls of hollow organs.

c. Cardiac muscle cells have multiple nuclei.

d. Smooth muscle cells are long and cylindrical.

e. There is a small amount of smooth muscle in the heart.
3. Which type of muscle tissue has cells that branch?
a. skeletal muscle

b. smooth muscle

c. cardiac muscle

d. both skeletal and cardiac muscle

e. both cardiac and smooth muscle
4. Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the
a. number of muscle fibers.

b. size of muscle fibers.

c. number of striations.

d. number of nuclei within the muscle fibers.

e. number of muscle cells.
5. Actin myofilaments
a. resemble bundles of minute golf clubs.

b. contain both myosin and tropomyosin.

c. are held in place by the M line.

d. contain strands of fibrous actin.

e. are the thickest proteins in muscle.
6. When an action potential reaches the presynaptic terminal,
a. calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.

b. acetylcholine moves into the presynaptic terminal.

c. a local potential is generated in the presynaptic terminal.

d. ligand-gated ion channels in the presynaptic terminal are opened.

e. nothing else happens.
7. In excitation-contraction coupling,
a. calcium ions must bind with myosin to expose active sites on actin.

b. myosin heads bind to exposed active sites on actin.

c. cross-bridges form between myosin heads and calcium ions.

d. movement of the troponin-tropomyosin complex causes actin myofilaments to slide.

e. ATP binds to actin myofilaments.
8. Which of the following helps explain the increased tension seen in multiple wave summation?
a. increased motor unit recruitment

b. increased concentration of calcium ions around the myofibrils

c. exposure of more active sites on myosin myofilaments

d. the breakdown of elastic elements in the cell

e. decreased stimulus frequency
9. An isotonic contraction is described as
a. action potential frequency is high enough that no relaxation of muscle fibers occurs.

b. a muscle produces constant tension during contraction.

c. a muscle produces an increasing tension during contraction.

d. a muscle produces increasing tension as it shortens.

e. a muscle produces tension, but the length of the muscle is increasing.
10. Which type of respiration occurs in the mitochondria?
a. anaerobic respiration

b. aerobic respiration

 

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