Chapter 11: Muscular System Flashcards Preview

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Flashcards in Chapter 11: Muscular System Deck (123)
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61

What separates the Schwann cells & the entire muscle cell from surrounding tissue?

basal lamina

62

What does the basal lamina contain?

acetylcholinesterase (AChE) to break down ACh after contraction causing relaxation

63

What helps hold the synaptic knob in place?

Schwann cells & basal lamina

64

voltage=______ def?

electrical potential; a dif in electrical charge from one point to another

65

What is the resting membrane potential?How is it maintained?

about -90mV; Na-K pumps

66

What is happening in an unstimulated resting cell? (3)

-more anions on the inside of the plasma membrane
-plasma membrane is polarized
-excess Na (ECF) and excess K (ICF)

67

What else is inside the ICF?

proteins, nucleic acids, and phosphates (all which cant penetrate the membrane)

68

What is happening in a stimulated muscle fiber?

-ion gates open in the plasma membrane
-Na moves inside (down concentration gradient)
-cations override negative charge of ICF (depolarization)
-Na gates close/ K open

69

What turns the membrane back into its negative state?

loss of positive K ions (repolarization)

70

action potential

quick up & down
polarized(resting)-> depolarization-> repolarization

71

what type of paralysis is tetanus?

spastic paralysis caused by C. tetani

72

flaccid paralysis

state in which the muscles are limp & cannot contract

73

botulism

type of food poisoning caused by neuromuscular toxin secreted by C. botulinum (prevent contraction)

74

What does the RMP shift to when Na is moved into the cell?

-90mV to +75mV

75

length tension relationship

amount of tension generated by a muscle & the force of contraction depends on how stretched/contracted it was before stimulated

76

What does the optimum resting length produce?

greatest force when muscle contracts

77

muscle tone

monitored by the nervous system that adjusts the length of the resting muscle & maintains a state of partial contraction

78

What does overly contraction cause?

crick in your neck

79

What does overly stretched cause?

actin filament have no myosin heads to attach to

80

rigor mortis

hardening of muscles & stiffening of body beginning 3 to 4 hours after death

81

muscle relaxation requires _____, which is no longer produced after death

ATP

82

myogram

chart of the timing & strength of a muscle contraction

83

_____, subthreshold electrical stimulus cause ___ contraction

weak; no

84

threshold

min voltage necessary to generate an action potential in the muscle fiber & produce contraction

85

twitch

quick cycle of contraction when stimulus is at threshold or higher

86

Twitches vary depending on?

-stimulus frequency
-concentration of Ca in sarcoplasma
-how stretched the muscle was
-temp of muscle

87

If the pH of the sarcoplasma is lower than normal, what happens?

fatigue

88

When stimulus intensity remains _____ twitch strength_____?

constant; vary with the stimulus frequency

89

10-20 stimuli per second produces what type of twitch? (staircase) describe

treppe; the muscle still recovers fully between twitches, but each twitch develops more tension than the one before

90

20-40 stimuli per second produces what? describe

incomplete tetanus (piggy back); each new stimulus arrived before the previous twitch is over