1. REVIEW SLIDES

2. NOTE:
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3. Chapter 12
Muscle

4. Describe a “twitch”

5. Describe a “twitch” A twitch is the rapid contraction and relaxation of a muscle fiber

6. Describe “summation”

7. Describe “summation”
In summation, the effects of many stimuli are added together to produce a muscle contraction

8. Describe ’recruitment’

9. Describe ’recruitment’
Recruitment is when many muscle fibers work together to produce a stronger contraction

10. Describe ‘tetanus”

11. Describe ‘tetanus”
A tetanus is when the summation of fiber twitches occurs rapidly enough that the muscle produces a smooth, sustained contraction

12. Calcium acts to stimulate muscle contraction by removing _______________ from actin so that actin can bind to myosin.

13. Calcium acts to stimulate muscle contraction by removing ____troponin___ from actin so that actin can bind to myosin.

14. The neurotransmitter secreted from somatic motor neurons is called _________________.

15. The neurotransmitter secreted from somatic motor neurons is called _acetylcholine___.

16. Acetylcholine stimulates contraction of skeletal muscle by binding to which acetylcholine receptor?

17. Acetylcholine stimulates contraction of skeletal muscle by binding to which acetylcholine receptor?
nicotinic

18. The oxygen storage molecule found in muscle is called ______________.

19. The oxygen storage molecule found in muscle is called ____myoglobin_.

20. Chicken legs and wings are Composed of dark meat
Chicken legs and wings are Composed of dark meat. What molecule is responsible for the darker color of this meat (as opposed to white meat)?

21. Chicken legs and wings are Composed of dark meat
Chicken legs and wings are Composed of dark meat. What molecule is responsible for the darker color of this meat (as opposed to white meat)? Myoglobin, a pigment which stores oxygen so that the endurance muscles have plenty of oxygen over time.

22. ____________________ contraction: A muscle fiber shortens when force is greater than load.
_____________________ contraction: A muscle may actually lengthen, despite contraction, if the load is too great.
Allows you to lower a weight gently after a full concentric contraction

23. __concentric__ contraction: A muscle fiber shortens when force is greater than load.
__eccentric__ contraction: A muscle may actually lengthen, despite contraction, if the load is too great.
Allows you to lower a weight gently after a full concentric contraction
See page 376

24. Describe concentric and eccentric contractions

25. Describe concentric and eccentric contractions
In a concentric contraction, a muscle fiber shortens when force is greater than load. In an eccentric contraction, a muscle may actually lengthen, despite contraction, if the load is too great.

26. Cardiovascular physiology
What is meant by the term “excitation-contraction coupling”?

27. What is meant by the term “excitation-contraction coupling”?
The membrane is excited (depolarized), and this causes muscle contraction. One event leads to the next.

28. Describe excitation-contraction coupling in a cardiac myocyte

29. Describe excitation-contraction coupling in a cardiac myocyte
A heart cell is stimulated by Na+ influx (from a gap junction)
This causes Ca2+ channels to open in the cell membrane (T-tubule)
Influx of Ca2+ causes Ca2+ channels in the SR membrane to open. (Ca2+ stimulated Ca2+ release)
Ca2+ enters cytoplasm, removes troponin from actin
Contraction occurs
heart muscle

30. The sliding filament theory of muscle contraction states that when the muscle shortens, the filaments

31. The sliding filament theory of muscle contraction states that when the muscle shortens, the filaments slide past one another.

32. Fig. 12.16 EXPLAIN THIS PICTURE Transverse tubule Sarcoplasmic
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Fig
EXPLAIN THIS PICTURE
Axon terminal
Sarcolemma
Ca2+ 3
Transverse
tubule
Transverse
tubule 4
Sarcoplasmic
reticulum
Sarcoplasmic
reticulum 1
Nicotinic acetylcholine receptor 3
Transverse tubule voltage-gated
calcium channel 2
Skeletal muscle voltage-gated
sodium channel 4
Sarcoplasmic reticulum calcium
release channel

33. EXPLAIN THIS PICTURE FIGURE 12.16, p. 372 Skeletal muscle
Acetylcholine stimulates influx of Na+ into muscle, which stimulates entry of calcium. The
Ca2+ channels are DIRECTLY LINKED to SR Ca2+ channels, which release Ca2+ into cytoplasm,
So that Ca2+ can remove troponin from actin
Axon terminal
Skeletal muscle
Sarcolemma
Ca2+ 3
Transverse
tubule
Transverse
tubule 4
Sarcoplasmic
reticulum
Sarcoplasmic
reticulum 1
Nicotinic acetylcholine receptor 3
Transverse tubule voltage-gated
calcium channel 2
Skeletal muscle voltage-gated
sodium channel 4
Sarcoplasmic reticulum calcium
release channel

34. Explain the significance of this graph
2.0 µm
2.25 µm
1.0
1.65 µm
Fig
Relative tension
0.5
1.25 µm
3.65 µm 60 80
100
120
140
160
Percentage rest length
1.65 µm
2.25 µm
3.65 µm

35. Explain the significance of this graph
As skeletal muscle is stretched, its contraction strength is lowered.
2.0 µm
2.25 µm
1.0
1.65 µm
Fig
Relative tension
0.5
1.25 µm
3.65 µm 60 80
100
120
140
160
Percentage rest length
1.65 µm
2.25 µm
3.65 µm

36. In skeletal muscle versus heart muscle, what is the difference between the locations of the calcium channels?

37. In skeletal muscle versus heart muscle, what is the difference between the locations of the calcium channels?
Calcium channels in skeletal muscle are DIRECTLY LINKED to SR Ca2+ channels, so there is an electromechanical release mechanism. There is also a calcium-induced calcium release mechanism. In cardiac myocytes, the receptors are not directly linked and therefore they ONLY have calcium-induced calcium release (see. P. 373)
Skeletal muscle
Cardiac muscle

38. CH 12
A person’s __________ is an expression of their maximal capacity for aerobic exercise.

39. CH 12
A person’s _VO2 max is an expression of their maximal capacity for aerobic exercise.
It is called the maximal oxygen uptake, or aerobic capacity
It can be increased by training.

40. The percentage of the maximal oxygen uptake at which a significant rise in blood lactate levels occurs is called the ____________ _______________.

41. The percentage of the maximal oxygen uptake at which a significant rise in blood lactate levels occurs is called the lactate threshold. (or anaerobic threshold)
Or average healthy people, a significant amount of blood lactate appears when the person is exercising at about 50-70% of their VO2 max.

42. During light exercise, most of the energy being used for skeletal muscle contraction comes from

43. During light exercise, most of the energy being used for skeletal muscle contraction comes from fatty acids.

44. As a person increases the intensity of their exercise from light to moderate, the body goes from utilizing mainly fatty acids to using a combination of ____________ and ___________.

45. As a person increases the intensity of their exercise from light to moderate, the body goes from utilizing mainly fatty acids to using a combination of fatty acids and glucose_.

46. _________________ from stored glycogen supplies most (66%) of energy during heavy exercise.

47. _glucose_ from stored glycogen supplies most (66%) of energy during heavy exercise.

48. Glycogen is made up of long chains of ___________ that when polymerized do not significantly alter the osmolality of the cell.

49. Glycogen is made up of long chains of glucose that when polymerized do not significantly alter the osmolality of the cell.

50. _________________ is the amount of oxygen you owe your body to re-fuel the lost oxygen stores, such as those in hemoglobin and myoglobin, and the reversal of lactate  pyruvate.

51. Oxygen debt is the amount of oxygen you owe your body to re-fuel the lost oxygen stores, such as those in hemoglobin and myoglobin, and the reversal of lactate  pyruvate.

52. _____________________ is a molecule that releases phosphate to ADP to make ATP.

53. _Creatine phosphate is a molecule that releases phosphate to ADP to make ATP.

54. The formation of creatine phosphate is catalyzed by an enzyme called

55. The formation of creatine phosphate is catalyzed by an enzyme called creatine kinase. (Or creatine phosphokinase).

56. When a person is doing high-intensity exercise, phosphocreatine helps because it

57. When a person is doing high-intensity exercise, phosphocreatine helps because it transfers a phosphate to ADP to make some quick ATP
Long term effects suggest possible liver damage by taking creatine supplements

58. Elevated levels of creatine kinase in the blood can indicate

59. Elevated levels of creatine kinase in the blood can indicate myocardial infarction.

60. Endurance muscle fibers are called ____________ twitch.

61. Endurance muscle fibers are called _slow_ twitch.
Or slow oxidative fibers

62. Slow twitch muscle fibers have a rich supply of

63. Slow twitch muscle fibers have a rich supply of myoglobin

64. Fast-twitch type II fibers have fewer capillaries and mitochondria than slow-twitch fibers and not as much myoglobin; hence these fibers are also called

65. Fast-twitch type II fibers have fewer capillaries and mitochondria than slow-twitch fibers and not as much myoglobin; hence these fibers are also called white fibers

66. Fast-twitch fibers use primarily the ______________ pathway as an energy source.

67. Fast-twitch fibers use primarily the glycolytic (or anaerobic) pathway as an energy source.

68. Muscle fatigue is the reversible, exercise-induced reduction in the ability of a muscle to generate force.
Muscle fatigue appears to be due to an accumulation of extracellular _______ ion.

69. Muscle fatigue is the reversible, exercise-induced reduction in the ability of a muscle to generate force.
Muscle fatigue appears to be due to an accumulation of extracellular _K+_ ion. Among other things (see p. 382)

70. All fiber types adapt to endurance training by an increase in _______________ and____________.

71. All fiber types adapt to endurance training by an increase in mitochondria and aerobic respiratory enzymes.

72. Skeletal muscles contain stretch receptors called _____________ ___________

73. Skeletal muscles contain stretch receptors called muscle spindles.

74. _________________ also called ______________ disease, results from the degeneration of upper and lower motoneurons that control skeletal muscle. This can lead to progressive muscle weakness, atrophy, and spastic paralysis, and death.

75. ALS (amyotrophic lateral sclerosis) also called Lou Gehrig’s disease, results from the degeneration of upper and lower motoneurons that control skeletal muscle. This can lead to progressive muscle weakness, atrophy, and spastic paralysis, and death.