Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology final > muscular system > Flashcards

muscular system Flashcards

1
Q

Functions muscle tissue

A
  1. Movement (movement of body parts, transport of materials)
  2. Stabilization (body postures, organ function)
  3. Thermogenesis (predominantly skeletal muscle)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

General characteristics of muscle tissue

A
  1. Possess irritability, contractility, extensibility, and elasticity
  2. Composed of elongated cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Location: somatic/skeletal muscles

A

upper part of esophagus, diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A muscle is surrounded by

A

epimysium (composed of dense connective tissue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The muscle is made up of bundles of muscle cells called

A

(fascicles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

bundles of muscle cells (fascicles), is covered by

A

perimysium

composed of dense connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

fascicle is made up of numerous muscle cells/”fibers”, each covered by

A

endomysium (consisting of a basal lamina)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

At the myotendinous junction, the endomysium, perimysium, and epimysium become continuous with the

A

muscle tendon, which attaches the muscle to the bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

the cell membrane of a muscle fiber

A

Sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

continuous with the sarcolemma, extending into the interior of the fiber, surrounding the myofibrils

A

Transverse tubules (aka, T tubules)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

specialized endoplasmic reticulum, forms a tubular network around the myofibrils

A

Sarcoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

large chambers of sarcoplasmic reticulum encircling the myofibril, on either side of the transverse tubule; storage of calcium ions

A

Cisternae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

unit of a transverse tubule and flanking cisternae encircling a myofibril

A

Triad

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

made up of microfilaments (aka, myofilaments), arranged into sarcomeres

A

Myofibril

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

made up primarily of the contractile protein actin

i. Also contain the regulatory proteins, troponin and tropomyosin
ii. Held in place by the structural protein nebulin, which attaches the…………………. to the Z disc

A

Thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

made up primarily of the protein myosin

Held in place by the structural protein, titin, which attaches the ……………….. to the Z disc and to the M line

A

Thick filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Additional structural protein that makes up the M line

A

Myomesin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Additional structural protein that connects thin filaments to the sarcolemma of the cell, thus helping to transmit muscle tension to the muscle tendon

A

Dystrophin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

the functional unit of muscle contraction

A

Sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

dark band, primarily made up of thick filaments

A

A band

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

center of the A band, made up of the structural protein myomesin, holding the thick filaments in place

A

M line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

lighter zone on either side of the M line, contains only thick filaments

A

H zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

overlapping zone of thin and thick filaments

A

Zone of overlap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

light band, made up entirely of thin filaments

A

I band

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

boundary between two sarcomeres, made up of the structural protein actinin, which holds the thick and thin filaments in place

A

Z disc/line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

…………………stimulated by signals from the nervous system; this generates an action potential (i.e., an electrical impulse) which travels down the…………………..

A

Sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Action potential travels through the……………… to the………………………

A

T tubules, myofibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Action potential triggers release of

A

calcium ions from the cisternae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Calcium ions (Ca2+) cause exposure of binding sites on the

A

actin molecules of the thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Calcium ions bind to …………………., causing…………………… to move away and uncover the binding sites on the actin molecules

A

troponin, tropomyosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What causes the thin filaments to slide past the thick filaments, toward the M line, resulting in contraction of the muscle fiber

A

Myosin binding to actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Myosin head binds to an actin molecule on the thin filament; this causes the release of

A

phosphate group (Pi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Before contraction of sarcomere begins, ……………………… binds to the myosin head and immediately hydrolyzes into………………….. , a …………………….., and……………………

A

adenosine triphosphate (ATP),adenosine diphosphate (ADP),phosphate group (Pi) and stored energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Release of the Pi initiates the ‘power stroke,’ which pulls the thin filament

A

toward the center of the sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

at the end of the power stroke, the…………………….is released from the myosin head

A

ADP molecule

36
Q

Another ATP molecule attaches to the myosin head, which causes the

A

myosin head to detach from the actin molecule

37
Q

due to permanent cross-bridging between actin and myosin because no ATP is available to break the bond

A

Rigor mortis

38
Q

Energy sources stored within the muscle (anaerobic)

A

Breakdown of creatine phosphate

39
Q

Energy sources stored within the muscle and in the liver (anaerobic)

A

Glycolysis of glycogen

40
Q

……………………………… of lipids, carbohydrates, and proteins (aerobic)

A

Oxidative metabolism

41
Q

immediate utilization of creatine phosphate and glycogen (anaerobic)

A

Phase I

42
Q

aerobic breakdown of fatty acids, carbohydrates, and proteins

A

Phase 2

43
Q

return to glycolysis (anaerobic) of glycogen remaining within the muscle

A

Phase 3

44
Q

embedded within the muscle belly; monitors changes in muscle length (both shortening [i.e., contraction] and lengthening [i.e., stretch])

A

Muscle spindle

45
Q

Intrafusal muscle fibers (specialized skeletal muscle cells) enclosed within a spindle-shaped connective tissue capsule; no actin or myosin filaments in the central portion of each intrafusal muscle fiber, only nuclei (structure of muscle spindles)

A

i. Nuclear bag fibers

ii. Nuclear chain fibers

46
Q

sensory nerve endings (type Ia) are wrapped around the center of both nuclear bag fibers and nuclear chain fibers

A

Primary ending

47
Q

sensory nerve endings (type II) are wrapped around the center of only the nuclear chain fibers

A

Secondary ending

48
Q

Gamma motor nerve fibers that predominantly innervates nuclear bag intrafusal fibers

A

Gamma-dynamic (gamma-d)

49
Q

Gamma motor nerve fibers that predominantly innervates nuclear chain intrafusal fibers

A

Gamma-static (gamma-s)

50
Q

i. Primary and secondary sensory endings fire continuously and in proportion to the degree of stretch
ii. Gamma-static motor fibers fire, proportionate to the increase or decrease in stretch

A

Slow, prolonged stretch: “static” response

51
Q

i. Primary sensory endings fire, only while change in length is occurring
ii. Gamma-dynamic motor fibers fire, maintaining spindle fiber length proportions, and thereby maintaining receptor sensitivity

A

Sudden stretch: “dynamic” response

52
Q

stretch receptor located at the myotendinous junction

A

Tendon organ (aka, Golgi tendon organ)

  1. Small bundle of tendon collagen fibers surrounded by a connective tissue sheath, one end connected to muscle fibers, the other end merging into the tendon
  2. A single type Ib sensory fiber wraps around the collagen fibers of the tendon organ
  3. Tendon organ fires in response to tension on the organ, due to either muscle contraction or muscle stretch
  4. Has both dynamic and static response levels
53
Q

a. Muscle is stretched suddenly, thereby stretching the muscle spindle; primary sensory fibers are activated (“dynamic response”) and action potentials travel into the spinal cord, synapsing directly with alpha motor neurons associated with that muscle (i.e., the homonymous muscle)
b. Alpha motor neurons of the homonymous muscle are activated and cause the muscle to contract, thereby decreasing the stretch on the muscle and returning the muscle spindles to their original length and returning the firing rate of the primary sensory fibers to their baseline (“static”) level
c. At the same time, motor commands are sent from the spinal cord to contract synergistic muscles and relax antagonistic muscles

A

Reflex cycle

54
Q

a. Prevent the development of too much tension within the muscle, protecting the muscle and tendon from potential damage
b. Equalizes the contraction strength of muscle fibers within a muscle

A

Functions of the Golgi tendon

55
Q

stimulation of a body part causes contraction of flexor muscles, withdrawing the body part away from the stimulus

A

Flexor-withdrawal reflex

56
Q

spread the reflex signal to other associated muscles

A

Diverging neural circuits

57
Q

inhibiting contraction of associated antagonist muscles

A

Reciprocal inhibition circuits

58
Q

prolonging the contraction of the flexor muscles after the stimulus has stopped

A

Circuits which cause an afterdischarge

59
Q

extension of contralateral limb, 0.2 to 0.5 seconds after the beginning of the flexor-withdrawal reflex

A

Crossed-extensor reflex

60
Q

Cells are striated, with actin and myosin arranged into sarcomeres

Cells are short and branched, with a single nucleus

A

Cardiac muscle tissue

61
Q

Cardiac muscle tissue what is larger and more plentiful than in skeletal muscle cells

A

Mitochondria

62
Q

Cardiac muscle tissue what is more numerous and larger (in diameter) than in skeletal muscle cells

A

Transverse tubules

63
Q

Cardiac muscle tissue what is less well developed than in skeletal muscle cells

A

Sarcoplasmic reticulum

64
Q

Sources of calcium during cell contraction

A

a. Released from cisternae of the sarcoplasmic reticulum
b. Extracellular fluid: calcium brought into the cell via the transverse tubules and diffuses across the cell membrane into the cell’s interior

65
Q

Cardiac cells originate from

A

a single myoblast

66
Q

Cardiac Cells interconnected to each other via

A

intercalated discs

67
Q

region consisting of numerous adherent junctions (viz., desmosomes) and numerous gap junctions

A

Intercalated discs

68
Q

keep the cells from pulling apart as they contract

A

Desmosomes

69
Q

act as ‘electrical synapses,’ passing the contraction signal directly from one cell to all the others within the interconnected network

A

Gap junctions

70
Q

all the cells within each network contract simultaneously, as if they were a single cell

A

Functional syncytium

Cells within the upper heart chambers (right and left atria) are all interconnected into a single network and the cells within the lower heart chambers (right and left ventricles) are all interconnected into a single network

71
Q
  1. Cells are short and fusiform in shape, with a single, centrally located nucleus
  2. Cells are not striated; actin and myosin are arranged differently from the sarcomeres of skeletal and cardiac muscle cells
  3. Sarcoplasmic reticulum is sparse and there are no transverse tubules
A

Smooth muscle Structure

72
Q

some scattered within the cell and some attached to the cell membrane

smooth muscle

A

Dense bodies

73
Q

some are bonded to membrane dense bodies of adjacent cells

smooth muscle

A

Membrane dense bodies

74
Q

In smooth muscle Actin filaments lack troponin; calcium instead binds to regulatory protein……………………….., associated with the myosin filaments

smooth muscle

A

calmodulin

75
Q

Myosin filaments interspersed in between………………

smooth muscle

A

actin filaments, halfway between the dense bodies

76
Q

structural proteins forming a framework for the actin and myosin filaments

smooth muscle

A

Intermediate filaments

77
Q

myosin heads on one side of the myosin molecule hinge (bend) in one direction, while heads on the opposite side hinge in the opposite direction

smooth muscle

A

‘Sidepolar’ cross-bridges between myosin and actin

Resulting cell shortening proceeds from a spiral, corkscrew-like contraction

78
Q

Little calcium is stored within the …………………..; most comes from extracellular fluid, and enters the cell through ……………………………. in the sarcolemma

smooth muscle

A

sarcoplasmic reticulum,calcium channels

79
Q

Numerous cells are arranged into a single sheet of interconnected cells, which all contract simultaneously

Typically found in hollow organs (e.g., stomach, intestines, uterus, bile duct, bladder, most blood vessels)

A

VISCERAL (aka, unitary, syncytial, single-unit) SMOOTH MUSCLE

(Cells are connected by numerous gap junctions, which transmit action potentials (as well as ions) between cells)

(Most organs have two layers of muscles, one running longitudinally, the other running transversely; the stomach has a third layer, running obliquely to the other two)

80
Q

Composed of individual smooth muscle cells, unconnected to nearby cells

i. Each cell is covered by a thin membrane (composed of fine collagen fibers and glycoproteins) which insulates it from nearby cells
ii. Each cell receives its own innervation
iii. Found in the constrictor and dilator muscles of the iris, arrector pili muscle, pulmonary air passages, and the walls of the largest arteries

A

Multi-unit smooth muscle

81
Q

Calcium-calmodulin complex binds to, and activates

A

myosin light chain kinase (MLCK)

82
Q

MLCK phosphorylates one of the light chains within a myosin head

A

allows the myosin head to bind to actin

83
Q

Myosin-actin cross-bridge cycle repeats until

A

available calcium is depleted; cycle is slower than in skeletal muscle (cross-bridge is intact for a longer period of time)

84
Q

Myosin light chain is de-phosphorylated by action of

A

myosin phosphatase

85
Q

T/F Onset and relaxation of contraction is much slower than in skeletal and cardiac muscle

A

T

a. Calcium channels open much more slowly, slowing the entry of calcium into the cell; channels stay open longer as well
b. Slow removal of calcium by calcium pumps

86
Q

T/F Lengthening of the cross-bridge cycle, in combination with the slowness of contraction onset and relaxation, produces a prolonged muscle tone without excessive energy expenditure

A

T

87
Q
  1. Nervous input: the predominant stimulus for multi-unit smooth muscle, less common for single-unit smooth muscle
  2. Hormonal input
  3. Muscle cell stretch
  4. Nearby chemical environment of the muscle cell (e.g., lack of oxygen, excess carbon dioxide, increased hydrogen ion concentrations)
A

Regulation of smooth muscle contraction

Physiology final (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions