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AP Psychology Practice Quiz: The Neuron and Neural Firing

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 16 questions to check your progress.

Question 1 of 16

According to the all-or-nothing principle, what happens once a neuron's threshold is reached?

All Questions (16)

According to the all-or-nothing principle, what happens once a neuron's threshold is reached?

A) The neuron fires with an intensity proportional to the strength of the stimulus.

B) The neuron fires with the same intensity every time.

C) The neuron enters a prolonged refractory period.

D) The neuron releases a mix of excitatory and inhibitory neurotransmitters.

Correct Answer: B

The provided content states that neural transmission involves the all-or-nothing principle. This principle dictates that a neuron either fires completely or not at all; the strength of the action potential is consistent and not graded based on the stimulus strength.

A psychoactive drug that encourages neural firing by mimicking the effects of a neurotransmitter is known as a(n):

A) Antagonist

B) Agonist

C) Reuptake inhibitor

D) Glial cell

Correct Answer: B

The content defines an agonist as a psychoactive drug that encourages firing. This is contrasted with an antagonist, which discourages firing, and a reuptake inhibitor, which blocks reabsorption.

In a spinal cord reflex arc, what is the function of interneurons?

A) To carry sensory information from the stimulus to the spinal cord.

B) To carry commands from the spinal cord to the muscles.

C) To provide physical support and nutrients to other neurons.

D) To communicate between sensory and motor neurons.

Correct Answer: D

The content specifies that the reflex arc demonstrates how sensory neurons, motor neurons, and interneurons work together. Interneurons serve as the connection point within the spinal cord, linking the incoming sensory information to the outgoing motor command.

Which of the following drug categories, including examples like alcohol, typically works by decreasing neural activity?

A) Stimulants

B) Depressants

C) Hallucinogens

D) Opioids

Correct Answer: B

The provided text explicitly states that depressants, such as alcohol, typically decrease neural activity.

A drug that functions as a reuptake inhibitor has its effect by:

A) Discouraging the neuron from firing by blocking receptor sites.

B) Increasing neural activity by mimicking excitatory neurotransmitters.

C) Blocking the reabsorption of neurotransmitters into the presynaptic neuron.

D) Causing distortions in perception and cognition.

Correct Answer: C

Point 9 in the content defines reuptake inhibitors as drugs that block reabsorption. This action leaves more neurotransmitters in the synapse, increasing their effect on the postsynaptic neuron.

When a person requires larger doses of a drug like heroin to achieve the same pain-relieving effects, they have developed:

A) Withdrawal

B) Depolarization

C) Tolerance

D) An inhibitory message

Correct Answer: C

The content states that psychoactive drug use can lead to tolerance, which is the need for increased amounts of a substance to achieve the desired effect.

What are the two types of messages that neurotransmitters can communicate?

A) Agonist and antagonist

B) Psychological and physiological

C) Sensory and motor

D) Excitatory and inhibitory

Correct Answer: D

Point 7 of the content directly states that 'Neurotransmitters have specific functions and communicate either excitatory or inhibitory messages.'

Within the nervous system, which cells are primarily responsible for providing support to neurons?

A) Motor neurons

B) Sensory neurons

C) Glial cells

D) Interneurons

Correct Answer: C

The provided content specifies that neurons transmit information while glial cells provide support, making them the basis of the nervous system.

The brief period after a neuron fires, during which it cannot fire again, is known as the:

A) Resting potential

B) Threshold

C) Reuptake phase

D) Refractory period

Correct Answer: D

Point 6 lists the key components of neural transmission, including the refractory period, which is defined as the recovery time after firing before a neuron can generate another action potential.

A drug that discourages neural firing by blocking a neurotransmitter's receptor site is a(n):

A) Antagonist

B) Agonist

C) Stimulant

D) Hormone

Correct Answer: A

The content defines an antagonist as a psychoactive drug that discourages firing. Blocking a receptor site is a common mechanism for this action.

Marijuana is classified as a hallucinogen because it typically causes:

A) An increase in neural activity.

B) A decrease in neural activity.

C) Distortions in perception or cognition.

D) Pain relief.

Correct Answer: C

Point 13 of the content explicitly states that hallucinogens, with marijuana as an example, typically cause distortions in perception or cognition.

How do hormones differ from neurotransmitters according to the provided information?

A) Hormones are only inhibitory, while neurotransmitters can be excitatory.

B) Hormones perform similar actions but outside of the nervous system.

C) Hormones are a type of psychoactive drug, while neurotransmitters are not.

D) Hormones are transmitted by glial cells, while neurotransmitters are transmitted by neurons.

Correct Answer: B

The content distinguishes between the two by stating that 'Hormones perform actions similar to neurotransmitters outside of the nervous system.' This highlights a difference in their domain of action.

Cocaine and caffeine are examples of which class of psychoactive drugs?

A) Depressants

B) Opioids

C) Hallucinogens

D) Stimulants

Correct Answer: D

The content lists caffeine and cocaine as examples of stimulants, which are drugs that typically increase neural activity.

The process of depolarization is essential for neural transmission because it is the event that:

A) Returns the neuron to its resting potential.

B) Clears neurotransmitters from the synapse.

C) Initiates the action potential once the threshold is crossed.

D) Prevents the neuron from firing too frequently.

Correct Answer: C

Depolarization, mentioned in point 6, is the shift in electrical charge that occurs during the action potential. Reaching the threshold triggers this rapid depolarization, which constitutes the 'firing' of the neuron.

Heroin is classified as an opioid because its primary function is to act as a(n):

A) Pain reliever

B) Perceptual distorter

C) Neural activity accelerator

D) Neural activity suppressor

Correct Answer: A

The provided text states that opioids, such as heroin, 'typically act as pain relievers.'

The fundamental way that the structures and functions of neurons affect behavior and mental processes is by:

A) Providing a supportive structure for the brain.

B) Transmitting information throughout the nervous system.

C) Releasing hormones into the bloodstream.

D) Creating tolerance and withdrawal symptoms.

Correct Answer: B

This question synthesizes points 1, 2, and 4. The core function of a neuron is to transmit information. This process of neural transmission is the basis for all behavior and mental processes.