Ch. 10 Review Questions

9. Fill in each blank with the correct answer from the key. More than one answer may be correct. Key: (a) skeletal muscle (b) cardiac muscle (c) smooth muscle (1) striated and involuntary (2) striated and voluntary (3) not striated and involuntary (4) is present in wall of bladder (5) is located only in the heart (6) its fibers are giant, multinucleate cells (7) the individual muscle cells are called muscle fibers (8) has no A or I bands (9) it is located in the walls of hollow body organs (10) its extranuclear materials are called sarcoplasm instead of cytoplasm, and the plasma membrane is called the sarcolemma

1. b 2.a 3.c 4.c 5.b 6.a 7.a,c 8.c 9.c 10.abc

5. Match the level of skeletal muscle organization given in the key with its description: Key: (a) muscle (b) fascicle (c) fiber (d) myofibril (e) myofilament (1) rod-shaped organelle; made of sarcomeres (2) an organ (3) a bundle of cells (4) a group of large molecules (5) a cell

1. d 2. a 3. b 4. e 5. c

4. Write yes or no in each blank below to indicate whether each of the following narrows when a skeletal muscle fiber contracts. (1) H band (2) A band (3) I band (4) M line

1. yes 2. no 3. yes 4. no

9. Which region of the myofibril changes in length during contraction: the A band, the I band, or the Z disc?

I band shortens

8. The ions that first enter a muscle cell when an impulse passes over its sarcolemma and then trigger muscle contraction are (a) calcium, (b) chloride, (c) sodium, (d) potassium.

a

2. A fascicle is (a) a muscle, (b) a bundle of muscle cells enclosed by a connective tissue sheath, (c) a bundle of myofibrils, (d) a group of myofilaments.

b

1. The connective tissue that lies just outside the sarcolemma of an individual muscle cell is called the (a) epimysium, (b) perimysium, (c) endomysium, (d) endosteum.

c

6. The function of T tubules in muscle contraction is to (a) make and store glycogen, (b) release Ca2+ into the cell interior and then pick it up again, (c) transmit an impulse deep into the muscle cell, (d) make proteins.

c

7. Which fiber type would be the most useful in the leg muscles of a long-distance runner? (a) fast glycolytic, (b) slow glycolytic, (c) fast oxidative.

c

Which types of muscle tissue are striated? Which types are called visceral muscle? In which types are the muscle cells called fibers?

cardiac, skeletal; smooth, cardiac; skeletal, smooth

1. What structural similarities are shared by all muscle tissue? What are the unique functional properties of this tissue?

contain myofilaments actin and myosin (generate contractile forces); plasma membrane called a sarcolemma (cytoplasm is called sarcoplasm.); contractility, excitability, extensibility, elasticity

14. How can older adults prevent or reverse the effects of sarcopenia?

exercise

11. Which fiber type dominates in the lower limb muscles of Usain Bolt, the two time (2008 and 2012) Olympic gold medalist in the 100-meter dash?

fast glycolytic

8. Why is overlap of the thin and thick filaments essential for muscle contraction?

for attachment of myosin heads to actin for contraction

12. What changes are apparent in the muscle tissue of a boy with Duchenne muscular dystrophy?

muscle fibers are replaced with fat and connective tissue

5. Place the following structures in order from smallest to largest, and define each: myofibril, muscle fiber, myofilament, sarcomere.

myofilament, sarcomere, myofibril, muscle fiber

6. Which myofilaments are found only in the A band?

myosin, thick filaments

10. Differentiate a neuromuscular junction from a motor unit

neuromuscular junction is the connection between axon terminal and muscle cell, a motor unit is a single motor neuron and all the fibers it is involved with

4. What are the functional definitions of the origin and insertion of a muscle? In the limbs, what are the conventional definitions of a muscle's origin and insertion?

origin is the muscle attachment that does not move when contracting, insertion is attachment that does move when muscle contracts; proximal is origin, distal is insertion

3. Name the connective tissue that surrounds a fascicle.

perimysium

7. What are the functions of the terminal cistern and the T tubules?

release calcium ions

13. Why are skeletal muscle fibers multinucleated?

the fusion of multiple embryonic cells

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the blanks). (2) contains myosin heads

thick

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the blanks). (3) contains myosin

thick

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the). blanks (5) does not lie in the I band

thick

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the blanks). (1) contains actin

thin

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the blanks). (4) does not lie in the H zone

thin

3. Thick and thin myofilaments have different properties. For each phrase below, indicate whether the filament described is thick or thin (write thick or thin in the blanks). (6) attaches to a Z disc

thin