Question 1

If an incoming message is not strong enough to cause a neuron to fire, it may cause a shift in the electrical charge of just a tiny area of the neuron. This shift, which quickly fades away, is called a(n) ________.
A) resting potential
B) action potential
C) transitional polarization
D) graded potential

Accepted Answer

A graded potential is a shift in the electrical charge of a tiny area of the neuron that may not be strong enough to cause a full action potential. Resting potential refers to the electrical charge of a neuron at rest. Action potential refers to the brief electrical impulse that travels down the axon of a neuron, causing neurotransmitter release. Transitional polarization is not a commonly used term in neuroscience.

Question 2

When the electrical charge inside a neuron is negative in relation to the outside, the neuron is said to be in a state of ________.
A) shock
B) polarization
C) equilibrium
D) depolarization

Accepted Answer

When the electrical charge inside a neuron is negative in relation to the outside, it is in a state of polarization. This is the resting state of a neuron before it receives a stimulus to fire.

Question 3

When a neuron is polarized, ________.
A) both positive and negative ions are concentrated inside the neural membrane
B) positive ions are concentrated outside the neural membrane while negative ions are concentrated inside the membrane
C) negative ions are concentrated outside the neural membrane while positive ions are concentrated inside the membrane
D) both positive and negative ions are concentrated outside the neural membrane

Accepted Answer

When a neuron is polarized, positive ions (such as sodium ions) are concentrated outside the neural membrane while negative ions (such as chloride ions) are concentrated inside the membrane. This creates a difference in electrical charge between the inside and outside of the neuron, known as the resting potential.

Question 4

Which of the following is NOT true of neural impulses?
A) The incoming message must be above a certain threshold to cause a neural impulse.
B) The neuron fires in response to every impulse it receives.
C) Neural impulses travel at speeds ranging from 3 feet per second to 400 feet per second.
D) The neuron may fire during the relative refractory period.

Accepted Answer

Neurons do not fire in response to every impulse they receive, as the incoming message must be above a certain threshold to cause a neural impulse. This is known as the all-or-nothing principle. The other options are true: neural impulses require a certain threshold to be met, they travel at various speeds, and the neuron may fire during the relative refractory period.

Question 5

Another term for a neural impulse is a(n) ________ potential.
A) resting
B) kinetic
C) graded
D) action

Accepted Answer

A neural impulse is also known as an action potential. Resting potential is the baseline electrical charge of a neuron at rest, kinetic refers to motion, and graded potential refers to a temporary and localized change in electrical charge that can either increase or decrease the likelihood of an action potential being fired.

Question 6

A resting potential is the electrical charge across a neural membrane when ________ ions concentrate on the outside and ________ ions concentrate on the inside.
A) excess positive; excess negative
B) not enough negative; excess positive
C) excess negative; excess positive
D) not enough positive; excess negative

Accepted Answer

The resting potential is characterized by an excess of positive ions (mainly sodium ions) outside the neuron and an excess of negative ions (mainly potassium ions and negatively charged proteins) inside the neuron.

Question 7

Electrically charged particles found both inside and outside the neuron are ________.
A) ions
B) free radicals
C) nodes
D) follicles

Accepted Answer

Electrically charged particles found both inside and outside the neuron are ions, which are essential for the transmission of electrical signals in the nervous system. Free radicals and follicles are not typically associated with neuronal activity, and nodes (while important for nerve transmission) are not charged particles themselves.

Question 8

The level a neural impulse must exceed to cause a neuron to fire is called the ________.
A) threshold of excitation
B) kinetic potential
C) kinetic ceiling
D) polarization limit

Accepted Answer

The threshold of excitation is the minimum level of stimulation required for a neuron to generate an action potential, or to “fire”. It is the point at which the neuron’s membrane potential reaches a certain level of depolarization that triggers the opening of voltage-gated ion channels, leading to the rapid influx of positively charged ions (such as sodium) and the generation of an electrical impulse. Choices B, C, and D are not accurate terms for describing the firing threshold of neurons.

Question 9

Which of the following statements is true?
A) A neuron fires in response to every message it receives.
B) Signals above the threshold of excitation will prevent a neuron from firing.
C) Impulses in myelinated neurons may reach speeds of nearly 400 feet per second.
D) The strength (intensity) of a neuron's action potential depends on the strength of its excitation.

Accepted Answer

Impulses in myelinated neurons may reach speeds of nearly 400 feet per second. This is due to the insulation provided by the myelin that allows for the rapid conduction of signals along the axon. Option A and B are incorrect as a neuron does not fire in response to every message it receives, and signals above the threshold of excitation will cause a neuron to fire, not prevent it. Option D is also incorrect as the strength of a neuron's action potential is constant and not dependent on the strength of its excitation.

Question 10

When sodium ions flow into a neuron and depolarize it, they create ________.
A) an action potential
B) breakdown of the cell nucleus
C) a relative refractory period
D) internal combustion

Accepted Answer

When sodium ions flow into a neuron and depolarize it, they create an action potential which is a brief electrical impulse that is the basis for transmitting information within the nervous system.

Question 11

When enough sodium atoms have entered the neuron to make the inside positively charged relative to the outside, the neuron is said to be ________.
A) depolarized
B) resting
C) diffusing
D) polarized

Accepted Answer

When enough sodium atoms have entered the neuron to make the inside positively charged relative to the outside, the neuron is said to be depolarized. This is because the membrane potential has shifted towards a more positive value.

Question 12

During its resting state, the electrical charge inside the neuron is ________ the electrical charge outside the neuron.
A) smaller than
B) positive compared to
C) negative compared to
D) larger than

Accepted Answer

During its resting state, the electrical charge inside the neuron is negative compared to the electrical charge outside the neuron. This is due to the concentration of negatively charged ions inside the cell membrane, such as chloride and bicarbonate, and the concentration of positively charged ions outside the cell membrane, such as sodium and calcium. This difference in charge is commonly referred to as the resting membrane potential.

Question 13

"Depolarization," "absolute refractory period," and "threshold of excitation" are terms that apply most directly to ________.
A) brain wave patterns (EEGs)
B) neural synapses
C) computerized axial tomography
D) action potentials

Accepted Answer

"Depolarization," "absolute refractory period," and "threshold of excitation" all refer to the generation and transmission of electrical impulses (action potentials) in neurons, making D the most appropriate option. Brain wave patterns (EEGs) are measured on the scalp and reflect the overall activity of large groups of neurons, while neural synapses refer to the small gaps between neurons where neurotransmitters are released. Computerized axial tomography (CT) is a type of brain imaging that uses X-rays to visualize brain structures.

Question 14

A frog muscle is stimulated with an electric current but the muscle doesn't twitch. This probably happens because ________.
A) ionic balance has been restored
B) the synapses are underactive
C) the threshold of excitation was not reached
D) the graded potential is too great

Accepted Answer

The muscle not twitching because the threshold of excitation was not reached.

Question 15

An electrical charge occurs across the neural membrane when positive ions concentrate on the outside and negative ions concentrate on the inside, is known as ________.
A) the resting potential
B) flux
C) depolarization
D) the action potential

Accepted Answer

The electrical charge that occurs across the neural membrane when positive ions concentrate on the outside and negative ions concentrate on the inside is known as the resting potential.

Question 16

A neuron will fire ________.
A) in response to every impulse it receives
B) only when the incoming message is stronger than the neuron's threshold of excitation
C) only when the incoming messages are weaker than the neuron's threshold of excitation
D) only when it receives two incoming messages at the same time

Accepted Answer

A neuron will only fire when the incoming message is stronger than its threshold of excitation. This ensures that the neuron is selective in which messages it responds to and that the response is strong enough to pass on to other neurons in the network.

Question 17

Organisms or fluids attempting to enter the cell body of a neuron must first pass through the ________.
A) cell membrane
B) dendrite
C) axon
D) myelin sheath

Accepted Answer

The cell membrane is the outermost layer of a neuron and serves as a semi-permeable barrier, allowing only certain substances to pass through. Therefore, organisms or fluids attempting to enter the cell body of a neuron must first pass through the cell membrane.

Question 18

When a neuron is polarized, ________.
A) it cannot fire
B) the electrical charge inside is positive relative to the outside
C) sodium ions pass freely through the cell membrane
D) the electrical charge inside is negative relative to the outside

Accepted Answer

When a neuron is polarized, the electrical charge inside the cell is negative relative to the outside. This is because there are more negatively charged ions (such as chloride) inside the cell and more positively charged ions (such as sodium) outside the cell. This difference in charge is essential for the transmission of information along the neuron.

Question 19

The process by which a neuron is depolarized in a surge running down the length of an axon is called a(n)________ potential.
A) action
B) graded
C) kinetic
D) resting

Accepted Answer

The process described in the question is that of an action potential.

Question 20

When sodium ions flow into a neuron and depolarize it, we say the neuron has ________.
A) reached equilibrium
B) been neutralized
C) refracted
D) fired

Accepted Answer

When sodium ions flow into a neuron and depolarize it, it reaches a threshold level and fires an action potential. This is the point at which the neuron becomes activated and begins the process of transmitting an electrical signal down its axon.

Quiz 2: The Biological Basis of Behavior

If an incoming message is not strong enough to cause a neuron to fire, it may cause a shift in the electrical charge of just a tiny area of the neuron. This shift, which quickly fades away, is called a(n) ________.

When the electrical charge inside a neuron is negative in relation to the outside, the neuron is said to be in a state of ________.

When a neuron is polarized, ________.

Which of the following is NOT true of neural impulses?

Another term for a neural impulse is a(n) ________ potential.

A resting potential is the electrical charge across a neural membrane when ions concentrate on the outside and ions concentrate on the inside.

Electrically charged particles found both inside and outside the neuron are ________.

The level a neural impulse must exceed to cause a neuron to fire is called the ________.

Which of the following statements is true?

When sodium ions flow into a neuron and depolarize it, they create ________.

When enough sodium atoms have entered the neuron to make the inside positively charged relative to the outside, the neuron is said to be ________.

During its resting state, the electrical charge inside the neuron is ________ the electrical charge outside the neuron.

"Depolarization," "absolute refractory period," and "threshold of excitation" are terms that apply most directly to ________.

A frog muscle is stimulated with an electric current but the muscle doesn't twitch. This probably happens because ________.

An electrical charge occurs across the neural membrane when positive ions concentrate on the outside and negative ions concentrate on the inside, is known as ________.

A neuron will fire ________.

Organisms or fluids attempting to enter the cell body of a neuron must first pass through the ________.

When a neuron is polarized, ________.

The process by which a neuron is depolarized in a surge running down the length of an axon is called a(n) ________ potential.

When sodium ions flow into a neuron and depolarize it, we say the neuron has ________.