Chapter 9 Part 4 Flashcards Preview

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Flashcards in Chapter 9 Part 4 Deck (15)
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1
Q

Though exceedingly close, axonal ends and muscle fibers are always separated by a space called the _______.

A

synaptic cleft

2
Q

When a nerve impulse reaches the end of an axon at the neuromuscular junction, voltage-regulated ______ channels open and allow ______ to enter the axon.

A

When a nerve impulse reaches the end of an axon at the neuromuscular junction, voltage-regulated calcium channels open and allow Ca2+ to enter the axon.

3
Q

Ca2+ inside the axon terminal causes axonal vesicles to fuse with the axonal membrane. This fusion releases ______ into the synaptic cleft via ______.

A

Ca2+ inside the axon terminal causes axonal vesicles to fuse with the axonal membrane. This fusion releases ACh into the synaptic cleft via exocytosis.

4
Q

Binding of ACh to its receptors initiates an _______ in the muscle.

A

action potential

5
Q

Acetylcholine bound to ACh receptors is quickly destroyed by the enzyme _______.

A

Acetylcholinesterase

6
Q

What is the name for a transient depolarization event that includes polarity reversal of a sarcolemma (or nerve cell membrane) and the propagation of an action potential along the membrane?

A

Action Potential

7
Q

What is an action potential?

A

A transient depolarization event that includes polarity reversal of a sarcolemma (or nerve cell membrane)

And the propagation of an action potential along the membrane.

8
Q

____ and ____ diffuse in and the interior of the sarcolemma becomes less negative.

This event is called _______.

A

Na<strong>+</strong>and K+ diffuse in and the interior of the sarcolemma becomes less negative.

This event is called depolarization.

9
Q

In a polarized sarcolemma, the outside (extracellular) face is ______, while the inside face is ______.

The difference in this charge is called ______.

A

In a polarized sarcolemma, the outside (extracellular) face is positive, while the inside face is negative.

The difference in this charge is the resting membrane potential.

10
Q

In a polarized sarcolemma, the predominant extracellular ion is ____.

While the predominant *intracellular *ion is ____.

A

In a polarized sarcolemma, the predominant* extracellular* ion is Na+.

While the predominant intracellular ion is K+.

11
Q

When Na+ enters the cell, the resting potential is ______ and ______ occurs.

If the stimulis is strong enough, an ______ is initiated.

A

When Na+ enters the cell, and the resting potential is decreased** and **depolarization occurs.

If the stimulis is strong enough, an action potential is initiated.

12
Q

Repolarization occurs in the same direction as depolarization, and must occur before the muscle can be stimulated again. This is called the _______.

A

Repolarization occurs in the same direction as depolarization, and must occur before the muscle can be stimulated again. This is called the refractory period.

13
Q

What restores the ionic concentration of the resting state?

A

The ionic concentration of the resting state is restored by the Na+ - K+ pump

14
Q

What powers excitation-contraction coupling?

A

the hydrolysis of ATP powers excitation-contraction coupling.

15
Q

What occurs when the muscle is in a state of physiological inability to retract?

A

Muscle fatigue occurs when the muscle is in a state of physiological inability to retract.