Chapter 11 - short - check

33. One somatic motor neuron is stimulated by how many muscle fibers? A. 0 B. 1 C. 2 D. 3 E. 4

A. 0

48. A reason that muscle twitches become progressively stronger in treppe is A. Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it B. ATP is regenerated fasted than it is consumed c. myosin heads show faster and faster power strikes D. more and more acetylcholine is released with each stimulus E. as the muscle warms up, aerobic respiration is accelerated

A. Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it

29. The minimum stimulus needed to cause muscle contraction is called A. the threshold B. the latent period C. twitch D. recruitment E. innervation

A. The threshold

41. Which of the following would be caused by contraction of smooth muscle? A. goose bumps B. blood leaving the left ventricle of the heart C. elevating the eyebrows D. blinking the eyelids E. deep inspiration

A. goose bumps

43. As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must A. recruit more muscle fibers B. lower its threshold C. reduce its wave summation D. shift from isometric to isotonic contraction E. shift from slow-twitch to fast-twitch mode

A. recruit more muscle fibers

40. Cardiac muscle has very little capacity for regeneration because it lacks A. satellite cells B. endomysium C. sarcomeres D. dense bodies E. somatic nerve fibers

A. satellite cells

34. To stimulate muscle contraction, acetylcholine is released from the ___ into the synaptic cleft. A. synaptic knob B. junctional folds C. sarcoplasmic reticulum D. sarcolemma E. terminal cisterna

A. synaptic knob

27. In comparison to skeletal muscle, smooth muscle A. contracts more slowly but relaxes more rapidly B. contracts more rapidly but relaxes more slowly C. contracts and relaxes more slowly D. consumes more ATP to maintain a given level of muscle tension e. depends on a nerve fiber to supply the calcium needed for contraction

B. contracts more rapidly but relaxes more slowly

37. The process of bringing more motor units into use during a muscle contraction is called A. wave summation B. recruitment c. treppe D. incomplete tetanus E. complete tetanus

B. recruitment

35. The absence or inhibition of acetylcholinesterase at a synapse would lead to which of the following? A. flaccid paralysis B. tetanus C. atrophy D. numbness E. muscle wasting

B. tetanus

31. Which of the following is true concerning isotonic eccentric contraction? A. The muscle shortens but tension remains constant B. the muscle lengthens but tension remains constant C. the muscle tenses and shortens D. the muscle tenses but length remains unchanged E. the muscle lengthens and tension declines

B. the muscle lengthens but tension remains constant

38. Aerobic respiration produces approximately ____ more ATPs per glucose molecule than glycolysis does A. 12 B. 24 C. 36 D. 48 E. 100

C. 36

32. Which of the following has the largest mitochondria A. slow oxidative fibers B. fast glycolytic fibers C. cardiac muscle D. smooth muscle E. intermediate fibers

C. cardiac muscle

30. If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be A. fatigue B. treppe C. incomplete tetanus D. complete tetanus E. flaccid paralysis

C. incomplete tetanus

26. The contraction strength of smooth muscle is relatively independent of its resting length partly because A. it gets nearly all of its CA2+ from the extracellular fluid b. it does not have intercalated discs C. it does not have sarcomeres D. it is regulate by a length-tension relationship E. it is involuntary muscle

C. it does not have sarcomeres

39. Athletes who train at high altitudes increase their red blood cell count and thus increase their oxygen supply during exercise. Increased oxygen supply results in A. increased glycolysis B. increased use of myokinase C. longer aerobic respiration D. longer anaerobic fermentation E. reduced ATP consumption

C. longer aerobic respiration

28. Which of the following is very important for muscle to continue contraction during anaerobic respiration? A. cholinesterase inhibitors B. protease C. myokinase D. acetylcholinesterase E. acid phosphatase

C. myokinase

44. The protein that acts as a calcium receptor in skeletal muscle is A. F actin B. tropomyosin C. troponin D. titin e. dystrophin

C. troponin

50. Creatine kinase A. donates one of its phosphate group to ADP B. phosphorylates and activates certain enzymes in the sarcoplasm C. acts as a second messenger in muscle fibers D. catalyzes the transfer of phosphate from CP to ADP E. functions as a substitute for ATP during anaerobic fermentation

D. catalyzes the transfer of phosphate from CP to ADp

46. Exposure to Clostridium tetani causes continuous release of acetylcholine. What effect does this have on smooth muscle? A. flaccid paralysis B. spastic paralysis C. lockjaw D. no effect E. myocardial atrophy

D. no effect

49. The purpose of varicosities in motor nerve fibers in muscle physiology is A. to link the thin filaments to the inside of the sarcolemma in smooth muscle B. to reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down C. to enable each cardiac myocyte to directly stimulate its neighbors D. to release neurotransmitter onto smooth muscle cells E. to prevent single-unit smooth muscle cells from pulling apart

D. to release neurotransmitter onto smooth muscle cells

45. Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. These drugs A. prevent calcium from entering the sarcoplasmic reticulum of smooth muscle B. stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin C. prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle D. prevent calcium from entering cardiac muscle, thus slowing down the heart rate E. prevent calcium from entering smooth muscle, thus allowing the muscle to relax

E. prevent calcium from entering smooth muscle, thus allowing the muscle to relax

36. Which statement best describes the goal of medications used to treat myasthenia gravis? A. to increase the number of acetylcholine receptors B. to decrease the number of synaptic vesicles C. to promote multiple motor unit summation D. to inhibit CA2+ release from the sarcoplasmic reticulum E. to inhibit the function of cholinesterase

E. to inhibit the function of cholinesterase

2. A ark band formed by parallel thick filaments that partly overlap the thing filaments is known as an H band

False

5. The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years

False

1. extensibility refers to the ability of a muscle to stretch

True

3. The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber

True

4. Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers

True

6. A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis

True

7. An isometric contraction does not change muscle length

True

8. Some smooth muscle is autorhythmic

True

47. Dystrophin, the protein that is defective in muscular dystrophy is normally found A. between the outermost myofilaments and the sarcolemma of a muscle fiber B. As a transmembrane protein of the sarcolemma C. in the Z discs of skeletal and cardiac muscle D. in the dense bodies of smooth muscle E. bridging the gap between the sarcolemma and synaptic knob

a. between the outmost myofilaments and the sarcolemma of a muscle fiber

42. The triads of a muscle fiber consists of A. two A bands and one I band B. two T tubules and one terminal cisterna C. two terminal cisternae and one T tubule D. two thin myofilaments and one thick myofilament E. two thick myofilaments and one thin myofilament

c. two terminal cisternae and one T tubule