nervous system - action potentials and action potential conduction

Question 1

the 1st half of hyperpolarization occurs due to-
a) potassium efflux
b) sodium efflux
c) sodium influx
d) potassium influx

Answer 1

a) potassium efflux

Question 2

resting potential in a neuron is typically -
a) positive
b) negative
c) neutral

Answer 2

b) negative

Question 3

the 2nd half of hyperpolarization occurs primarily due to -
a) potassium influx
b) potassium efflux
c) sodium efflux
d) sodium influx

Answer 3

a) potassium influx

Question 4

what do we call the layer of fatty tissue surrounding the axon of some neurons?
a) dendrites
b) synapse
c) myelin

Answer 4

c) myelin

Question 5

the nodes on a myelinated neuron
a) contain the nuclei of the neuron
b) are not covered by schwann cells
c) are covered by schwann cells

Answer 5

b) are not covered by schwann cells

Question 6

which gates open and close slowly
a) K+ gates
b) Na+ activation gates
c) Na+ inactivation gates

Answer 6

a) K+ gates

Question 7

repolarization occurs primarily due to
a) potassium influx
b) sodium efflux
c) potassium efflux
d) sodium influx

Answer 7

c) potassium efflux

Question 8

during the second half hyperpolarization, potassium returns to the inside of the cell. this is due primarily to the
a) concentration gradient
b) pressure gradient
c) electrical gradient

Answer 8

c) electrical gradient

Question 9

which of the following will increase the speed of conduction? select all that apply
a) increased diameter
b) increased myelin
c) increased temperature
d) increased length

Answer 9

a, b, c

Question 10

what causes the end of depolarization?
a) Na+ activation gates close
b) Na+ activation gates open
c) Na+ activation gates open
d) Na+ inactivation gates close

Answer 10

d) Na+ inactivation gates close

Question 11

during the second half of hyperpolarization, potassium returns to the inside of the cell. this is due primarily to the
a) concentration gradient
b) pressure gradient
c) electrical gradient

Answer 11

c) electrical gradient

Question 12

what gates are open during repolarization? select all that apply
a) Na+ activation gates
b) Na+ activation gates
c) K+ gates

Answer 12

b,c

Question 13

will a myelinated or unmyelinated neuron have a faster action potential?

Answer 13

myelinated

Question 14

what kind of voltage gates are found in the nodes between the myelin
a) sodium
b) calcium
c) potassium

Answer 14

a) sodium

Question 15

threshold in a neuron occurs at _____ mV

Answer 15

-55

Question 16

depolarization occurs primarily due to-
a) sodium efflux
b) potassium influx
c) potassium efflux
d) sodium influx

Answer 16

d) sodium influx

Question 17

why does increased temperature lead to an increased speed of action potential conduction?
a) higher temperature means ions are moving faster
b) higher temperature causes the diameter of the neuron to increase
c) higher temperature actually slows down action potential conduction

Answer 17

a) higher temperature means ions are moving faster

Question 18

resting potential in a neuron is typically _______ mV

Answer 18

-70

Question 19

what happens to cause the end of depolarization
a) Na+ inactivation gates open
b) Na+ activation gates close
c) Na+ inactivation gates open
d) Na+ activation gates open

Answer 19

c) Na+ inactivation gates open

Question 20

which of the following best describes saltatory conduction?
a) an impulse moves from the axon of one neuron, across the synapse, and to the dendrite of the next neuron
b) an impulse moves from one schwann cell to the next schwann cell along the length of the axon
c) an impulse moves from one node to the next node along the length of an axon

Answer 20

c) an impulse moves from one node to the next node along the length of an axon

Question 21

true or false: a myelinated neuron will have action potentials that literally jump between the nodes of ranvier

Answer 21

false

Question 22

true or false: myelin traps ions inside the cell

Answer 22

true