Action Potential

Question 1

The resting potential of a neuron is typically around _________ millivolts.
a. -70
b. 0
c. +70
d. +30

Answer 1

-70

Question 2

The first stage of an action potential is called the _______.
a. hyperpolarization
b. depolarization
c. repolarization
d. none of the above

Answer 2

depolarization

Question 3

The opening of __________ channels leads to depolarization of the neuron.
a. potassium
b. sodium
c. calcium
d. chloride

Answer 3

sodium

Question 4

During the absolute refractory period, the neuron cannot generate another action potential no matter how strong the stimulus. True or False?

Answer 4

True

Question 5

The all-or-nothing principle of action potentials means that the amplitude of the action potential is proportional to the strength of the stimulus. True or False?

Answer 5

False

Question 6

The ___________ is the point at which the action potential is propagated from the axon hillock to the axon.
a. axon terminal
b. synapse
c. myelin sheath
d. initial segment

Answer 6

initial segment

Question 7

In a myelinated axon, the action potential jumps from one node of Ranvier to the next in a process called ____________.
a. saltatory conduction
b. continuous conduction
c. synaptic transmission
d. none of the above

Answer 7

saltatory conduction

Question 8

The refractory period of a neuron is important because it ensures that action potentials do not overlap.
True or False?

Answer 8

True

Question 9

The ____________ is responsible for returning the neuron to its resting potential after an action potential.
a. sodium-potassium pump
b. calcium channel
c. chloride channel
d. potassium channel

Answer 9

potassium channel

Question 10

The speed of an action potential is affected by the __________ of the neuron.
a. diameter
b. length
c. number of dendrites
d. neurotransmitter concentration

Answer 10

diameter

Question 11

Which of the following is NOT a phase of the action potential?
a. Hyperpolarization
b. Depolarization
c. Repolarization
d. Polarization

Answer 11

Polarization

Question 12

The resting potential of a neuron is caused by:
a. A high concentration of potassium ions inside the neuron and a low concentration of sodium ions outside the neuron.
b. A high concentration of sodium ions inside the neuron and a low concentration of potassium ions outside the neuron.
c. A high concentration of chloride ions inside the neuron and a low concentration of sodium ions outside the neuron.
d. A high concentration of sodium ions inside the neuron and a low concentration of chloride ions outside the neuron.

Answer 12

A high concentration of potassium ions inside the neuron and a low concentration of sodium ions outside the neuron.

Question 13

Which ion is responsible for the depolarization phase of the action potential?
a. Potassium
b. Sodium
c. Calcium
d. Chloride

Answer 13

Sodium

Question 14

During the action potential, the membrane potential of the neuron reaches a peak of approximately:
a. -70 mV
b. -55 mV
c. +30 mV
d. +55 mV

Answer 14

+55 mV

Question 15

The refractory period of the action potential ensures that:
a. The action potential can only move in one direction.
b. The action potential can move in both directions.
c. The action potential does not occur.
d. None of the above.

Answer 15

The action potential can only move in one direction.

Question 16

The myelin sheath ___________ the speed of the action potential.

Answer 16

increases

Question 17

The resting potential of a neuron is caused by a high concentration of ___________ ions inside the neuron and a low concentration of ___________ ions outside the neuron.

Answer 17

potassium, sodium

Question 18

The __________________ helps to maintain the resting potential before an action potential.

Answer 18

sodium-potassium pump

Question 19

During depolarization, the inside of the neuron becomes more negative compared to the outside. True or false?

Answer 19

False

Question 20

The refractory period of the action potential ensures that the action potential can move in both directions. True or false?

Answer 20

False

Question 21

Action potentials can occur at different rates due to differences in the:
a. Axon diameter.
b. Length of the axon.
c. Type of neuron.
d. All of the above.

Answer 21

All of the above.

Question 22

The myelin sheath is a fatty layer that covers the axon and helps to increase the speed of the action potential. True or false?

Answer 22

True

Question 23

Which of the following channels are responsible for the repolarization phase of the action potential?
a. Sodium channels
b. Potassium channels
c. Calcium channels
d. Chloride channels

Answer 23

Potassium channels

Question 24

What is the threshold potential of a neuron?
a. The minimum amount of stimulus needed to cause an action potential
b. The maximum amount of stimulus that a neuron can handle
c. The potential difference across a neuron’s membrane at rest
d. The potential difference across a neuron’s membrane during an action potential

Answer 24

The minimum amount of stimulus needed to cause an action potential

Question 25

During hyperpolarization, the membrane potential of the neuron becomes more ___________ than the resting potential.

Answer 25

negative

Question 26

The opening of voltage-gated ___________ channels cause the release of neurotransmitters at the synaptic terminal.

Answer 26

calcium

Question 27

The all-or-none law states that the amplitude and velocity of an action potential are dependent on the strength of the stimulus. True or false?

Answer 27

False

Question 28

During an action potential, the membrane potential of a neuron becomes more positive. True or false?

Answer 28

True

Question 29

The absolute refractory period ensures that the action potential can only move in one direction. True or false?

Answer 29

True

Question 30

The nodes of Ranvier are unmyelinated sections of an axon. True or false?

Answer 30

True