Ch 12: Skeletal Muscles Flashcards Preview

Physiology Final > Ch 12: Skeletal Muscles > Flashcards

Flashcards in Ch 12: Skeletal Muscles Deck (121):
0

What happens when a muscle contracts?

It shortens

1

The bone that moves is attached at the muscle _________?

Insertion

2

The muscle is attached to a bone that does not move at the muscle _______?

Origin

3

________ muscles decrease the angle between two bones at a joint.

Flexor

4

________ muscles increase the angle between two bones at a joint.

Extensor

5

The prime mover of my skeletal movement is called the?

Agonist

6

Flexors and extensors that work together are?

Antagonists

7

Skeletal muscles are surrounded by a fibrous _____.

Epimysium

8

Each fascicle of a muscle is surrounded by the?

Perimysium

9

Connective tissues called perimysium subdivides the muscle into _______.

Fascicles

10

Each fascicle is subdivided into muscle fibers surrounded by ______.

Endomysium

11

Muscle fibers have a plasma membrane called what?

Sarcolemma

12

________ are multinucleated and striated.

Muscle fibers

13

The light band of a skeletal muscle is known as the?

I band

14

The dark band of a skeletal muscle is known as the

A band

15

The site where a motor neuron stimulates a muscle fiber is known as?

Neuromuscular junction

16

The area of the muscle fiber sarcolemma where a motor neuron stimulates it is?

Motor end plate

17

Somatic motor neurons release the neurotransmitter _______ at the neuromuscular junction.

Acetylcholine

18

Each somatic motor neuron with all the muscle fibers it innervates is a?

Motor unit

19

Subunits of skeletal muscle cells that are composed of sarcomeres are called?

Myofibrils

20

The thick filament is also called the?

A band

21

____ contain only thin filaments.

I bands

22

_____ are the center of the A band with no thin filament overlap.

H bands

23

______ are found in the center of each I band

Z lines

24

_______ are found in the center of each A band and help hold down thick filaments.

M lines

25

What is the area from one Z line to the next?

Sarcomere

26

The protein that anchors in the thick filaments and allows elastic to coil is known as?

Titin

27

When a muscle contracts, sarcomeres shorten and _______ do not shorten.

A bands

28

When a muscle contracts, sarcomeres shorten and ______ shorten, but thin filaments do not.

I bands

29

When a muscle contracts, sarcomeres shorten and thin filaments side toward the ______?

H zone

30

Thick myofilaments are composed of the protein ______.

Myosin

31

Myosin contains binding sites for ____and______ .

ATP, actin

32

Which molecule blocks the myosin head from binding to actin in a relaxed muscle?

Tropomyosin

33

Sliding is produced by several cross bridges that form between ______ and _______.

Myosin, actin

34

Release of Pi upon binding cocks the myosin head, producing a _________ that pulls the thin filament toward the center.

Power stroke

35

After the power stroke, ____ is released and a new ATP binds.

ADP

36

_____ inhibits binding of myosin.

Troponin I

37

_____ binds to tropomyosin.

Troponin T

38

____ binds to calcium.

Troponin C

39

When muscle cells are stimulated, _____ is released inside the muscle fiber.

Ca2+

40

_______ is modified endoplasmic reticulum that stores Ca2+ when muscle is at rest. Most is stored in terminal cisternae.

Sarcoplasmic Reticulum (SR)

41

When a muscle fiber is stimulated, Ca2+ diffuses out of ______.

Calcium release channels

42

What are narrow membranous tunnels formed from the sarcolemma, open to the extra cellular environment, able to conduct act own potentials, and closely situated next to terminal cisternae?

Transverse Tubules

43

When stimulating a muscle fiber, _______ is released from the motor neuron, and the end plate potentials are produced.

Acetylcholine

44

When stimulating a fiber, action potentials are generated and voltage gated calcium channels in transverse tubules change shape and cause calcium channels in the SR to open causing ____ to be released and bind to the Troponin C.

Calcium

45

____ is done in vitro where one end of the muscle is fixed and the other is movable.

Study

46

When studying ________, electrical simulations are applied and contractions are recorded and displayed as currents.

Muscle behavior

47

What is it called when a muscle quickly contracts and relaxes after a single electrical shock of sufficient voltage?

Twitch

48

What is it called when a second shock is applied immediately after the first, and giving a piggyback look?

Summation

49

What is it called when increasing the frequency of electrical shocks decreases the relaxation time between twitches?

Incomplete tetanus

50

What is it called when at a certain frequency there will be no relaxation?

Complete tetanus

51

The inability of muscle cells to relax due to high frequency stimulation is termed?

Tetanus

52

As the voltage is increased, the number of muscle fibers used in vitro increases. This will reach a maximum value when all Muscle fibers are stimulated. If a fresh muscle is stimulated with several shocks at maximum voltage, each twitch will be progressively stronger causing a staircase effect. This is known as what?

Treppe

53

Muscle fibers shorten when the tension produced is just greater than the load is known as what?

Isotonic contractions

54

Muscles can't shorten because the load is too great is known as what? (can be voluntary)

Isometric contractions

55

A muscle fiber shortens when force is greater than the load is known as what?

Concentric contractions

56

A muscle may actually lengthen, despite contraction, if the load is too great is known as what?

Eccentric contraction

57

_____ parts of the muscle and tendons must be pulled tight when muscles contract.

Noncontractile

58

______ are elastic, resist distension, and snap back to resting length. They also absorb some of the tension as muscles contract.

Tendons

59

__________ is determined by the number of fibers recruited to contract, frequency of stimulation, thickness of each muscle fiber ( thicker is stronger), and the initial length of the fiber at rest.

Muscle strength

60

_____ is maximal when sarcomeres are at normal resting length.

Tension

61

Increasing or decreasing sarcomeres length will _______ the muscle tension.

Decrease

62

Where do muscles get their energy when they are at rest or mild exercise?

Fatty acids

63

Where do muscles get their energy for moderate exercise?

Glycogen stores

64

Where do muscles get their energy from for heavy exercise?

Blood glucose

65

Determines whether a given exercise is light, moderate, or heavy for a given person Is called?

Maximal oxygen uptake

66

________ is determined by a person's age, sex, size, and athletic training.

Maximal oxygen uptake

67

________ is another way to determine exercise intensity for a given person.

Lactate threshold

68

When a person exercises, _______ is withdrawn from reserves in hemoglobin and myoglobin.

Oxygen

69

Breathing rate continues to be ______ after exercise to repay this debt.

Elevated

70

The first 1 to 2 minutes of moderate to heavy exercise relies on ____ for ATP production.

Anaerobic respiration of glucose

71

What twitch caused slower contraction speed, can sustain contraction for long periods without fatigue, rich capillary supply, more mitochondria, more respiratory enzymes, and more myoglobin(slow,red fibers)?

Slow (type I)

72

What twitch has high oxidative capacity?

Slow (type I)

73

What twitch has faster contraction speed, fatigue fast, fewer capillaries, mitochondria, respiratory enzymes, and less myoglobin?

Fast (type II)

74

Type I skeletal muscle fibers have _________.

Numerous mitochondria

75

What has a fast-twitch but with high oxidative capacity?

Intermediate (type IIA)

76

Which of the following is NOT a contributing factor to skeletal muscle fatigue?

Increased intracellular K+

77

Adaptation to endurance training decrease in type II and _______ in type IIA muscle fibers.

Increase

78

Type II muscle fibrils become thicker due to increased amount of actin and myosin (more sarcomeres) is known as what?

Hypertrophy

79

Skeletal muscles have stem cells called ______ located near muscle fibers.

Satellite cells

80

_____ is a paracrine regulator that inhibits satellite cells.

Myostatin

81

Muscle decline is due to what?

Aging

82

_______ is influenced by sensory feedback from muscles and tendons, and stimulation or inhibition from higher motor neurons from the brain.

Lower motor neurons

83

What responds to tension that a muscle puts on a tendon?

Golgi tendon organs

84

What responds to muscle length?

Muscle spindle apparatus

85

The muscle spindle apparatus is associated with _______ ?

Intrafusal fibers

86

What are the two types of muscle cells?

Nuclear bag fibers, nuclear chain fibers

87

What are two types of sensory cells wrap around the fibers?

Primary ( annulospiral)
Secondary ( flower-spray)

88

Innervate extrafusal (contracting) muscle fibers is called?

Alpha

89

Innervate Intrafusal (stretch) muscle fibers is called?

Gamma

90

The simplest reflex that only involves a sensory neuron synapsing on a motor neuron in the spinal cord is called?

Monosynaptic

91

What can be stimulated by striking the patellar ligament in the "knee jerk reflex"?

Monosynaptic stretch reflex

92

In the knee jerk reflex, interneurons are also stimulated in the spinal cord to inhibit antagonistic muscles on that limb is known as?

Reciprocal innervation

93

More complex reflexes require control of muscles on the contralateral limb is known as? (when you step on a tack)

Double reciprocal innervation

94

What sends neurons through the pyramidal tracts?

Precentral gyrus

95

What receives information from muscle spindles and golgi tendon organs as well as other senses?

Cerebellum

96

What also acts to inhibit motor activity through the rubrospinal tract?

Basal nuclei

97

______ and ______ muscles are involuntary and are regulated by the autonomic nervous system. The contraction is due to the myosin/actin cross bridges stimulated by calcium.

Cardiac, smooth

98

_______ muscles are striated, have myosin and actin filaments that form sarcomeres, and contraction occurs by means of sliding thin filaments.

Cardiac

99

Unlike skeletal muscle fibers (cells), these fibers are short, branched, and connected via gap junctions called _______.

Intercalated discs

100

A ________ is a mass of cardiac muscle cells connected to each other via gap junctions.

Myocardium

101

Action potentials that occur at any cell in a myocardium can stimulate all the cells in the _____.

Myocardium

102

The _____ of the heart compose one myocardium, and the ______ of the heart compose another myocardium.

Atria, ventricles

103

Cardiac muscle can produce action potentials automatically that begin in a region called _______.

Pacemaker

104

____ is influenced by autonomic innervation and hormones.

Heart rate

105

______ is found in blood vessel walls, bronchioles, digestive organs, urinary and reproductive tracts.

Smooth muscle

106

What muscle has no sarcomeres, long actin filaments attached to dense bodies, some myosin filaments, and allows contraction even when greatly stretched?

Smooth muscle

107

In smooth muscle cells, _______ functions in a manner analogous to Troponin.

Calmodulin

108

Multiple gap junctions that make neighboring cells behave as a unit is known as?

Single-unit

109

What require individual nerve innervation (no pacemaker activity)?

Multi-unit

110

_______ is released along the length of an autonomic neuron from varicosities.

Neurotransmitter

111

The more movable end of a Muscle is called the ______.

Insertion

112

The principle muscle responsible for a particular movement is called the _______.

Agonist

113

Each muscle fiber is surrounded by a connective tissue layer called the _____.

Endomysium

114

The structural and functional unit of muscle is the _____.

Sarcomere

115

Which of the following do not change in size during muscle contraction?

A band

116

Which of the following uses calmodulin part of the ECC process?

Smooth muscle

117

Calmodulin take the place of _____ in muscle contraction.

Troponin

118

The primary foodstuff for mild exercising muscle is_____.

Fatty acids

119

An increase in muscle cell size is called?

Hypertrophy

120

Which of the following does not add to the red color of muscle?

Mitochondria