physiology ch 5

Question 1

When another action potential could be generated if a greater than normal incoming stimulus is applied, the cell is in ______

Answer 1

Relative refractory period

Question 2

What is the main function of the K+ leak channels in a typical neuron?

Answer 2

Builds most of the negative charge inside the cell

Question 3

Alpha motor neurons release ______ which binds to _____ receptors on the motor endplate

Answer 3

acetylcholine, nicotinic

Question 4

Which is triggered to CLOSE at the peak voltage of a typical neuronal action potential?

Answer 4

Voltage gated sodium channels

Question 5

Which muscle would have the largest motor units?

Answer 5

Triceps brachii

Question 6

When another action potential cannot be generated regardless of how great an incoming stimulus is, the cell is in ______.

Answer 6

absolute refractory period

Question 7

Which muscle would have the largest motor units?

Answer 7

brachioradialis

Question 8

The influx of _____ in a typical neuron will cause hyperpolarization, as the membrane becomes more negative than resting membrane potential.

Answer 8

chloride

Question 9

Which type of neuron has the fastest conduction speed?

Answer 9

Type A alpha

Question 10

Which is usually opened to allow + current into a typical sensory neuron receptor to summate to threshold?

Answer 10

pressure gated sodium channels

Question 11

Which is triggered to CLOSE during the undershoot phase of a typical neuronal action potential?

Answer 11

Voltage gated potassium channels

Question 12

Which occurs when 2 or more presynaptic inputs arrive at a post-synaptic cell in rapid succession (quickly, one right after the other) to allow sufficient inward current to reach threshold?

Answer 12

temporal summation

Question 13

Which muscle would have the smallest motor units?

(hint; which contributes to the finest, most accurate motor activity)

Answer 13

flexor pollicis longus

Question 14

At resting membrane potential, the typical neuronal cell membrane is MOST permeable to _____.

Answer 14

potassium

Question 15

Which provides a lipid insulator to increase speed for saltatory conduction of nerve action potentials?

Answer 15

myelin

Question 16

The influx of _____ in a typical neuron will cause depolarization towards threshold.

Answer 16

sodium

Question 17

Which occurs during the undershoot of an action potential?

Answer 17

relative refractory period

Question 18

Which muscle would have the largest motor units?

Answer 18

coracobrachialis

Question 19

Which increases conduction velocity for a neuron?

Answer 19

Increasing the diameter of the nerve fiber

Question 20

Which is located along the dendrites and soma of a typical motor neuron to allow influx of + current to summate to threshold?

Answer 20

ligand gated sodium channels

Question 21

During saltatory conduction, the membrane only depolarizes at the ______.

Answer 21

Nodes of Ranvier

Question 22

Which occurs during an action potential when the inactivation gates of the sodium channels are closed?

Answer 22

Absolute refractory period

Question 23

During the repolarization phase of a neuron action potential, _____ is ______ the cell.

Answer 23

K+, leaving

Question 24

Which muscle would have the smallest motor units?

(hint; which contributes to the finest, most accurate motor activity)

Answer 24

extensor indices

Question 25

Which is triggered to OPEN at the peak voltage of a typical neuronal action potential?

Answer 25

Voltage gated potassium channels

Question 26

Which 2 factors would increase the speed of nerve conduction?

Answer 26

increased diameter of nerve axon + increased amount of myelination

Question 27

During the depolarization phase of a neuron action potential, _____ is ______ the cell

Answer 27

Na+, entering

Question 28

Which occurs when 2 or more presynaptic inputs arrive at a post-synaptic cell simultaneously (at the same time) to allow sufficient inward current to reach threshold?

Answer 28

Spatial summation

Question 29

Which is concentrated at the 1st node of Ranvier of a typical sensory neuron to trigger the depolarization phase of an action potential?

Answer 29

Voltage gated sodium channels

Question 30

Which muscle would have the smallest motor units?

(hint; which contributes to the finest, most accurate motor activity)

Answer 30

Flexor digiti minimi