Question 1

A subthreshold stimulus will not generate an action potential whereas a suprathreshold stimulus does generate an action potential. This is an example of

Accepted Answer

The all-or-none principle states that an action potential either occurs fully or not at all, depending on whether the stimulus reaches the threshold level. A subthreshold stimulus does not reach this level, so no action potential is generated, while a suprathreshold stimulus does, resulting in an action potential.

Question 2

In the peripheral nervous system, _ neurons carry sensory and visceral information to the central nervous system, and neurons leave the central nervous system and innervate organs, which are usually muscles or glands.

Accepted Answer

Afferent neurons carry sensory and visceral information to the central nervous system, while efferent neurons carry signals away from the central nervous system to innervate organs.

Question 3

Information gathered about our internal environment (i.e., fullness of the stomach, blood pressure, etc.)is called information.

Accepted Answer

Visceral information refers to the sensory data collected from the internal organs, such as the fullness of the stomach and blood pressure, which are part of the internal environment.

Question 4

What portion of the efferent branch of the nervous system communicates to glands and cardiac muscle?

Accepted Answer

The autonomic nervous system is responsible for controlling involuntary actions, such as the activity of glands and cardiac muscle.

Question 5

What portion of the peripheral nervous system communicates to effector organs?

Accepted Answer

The efferent nervous system is responsible for transmitting signals from the central nervous system to effector organs, such as muscles and glands, to elicit a response.

Question 6

Which of the following potentials can sum?

Accepted Answer

The answer of Which of the following potentials can sum?
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Question 7

Which of the following potentials is a result of opening or closing of ion channels?

Accepted Answer

Opening or closing of ion channels results in both graded potentials (which vary in amplitude and do not reach a threshold for an action potential) and action potentials (which have a fixed amplitude and always reach a threshold for depolarization of the cell membrane).

Question 8

In a neuron, where are voltage- gated calcium channels located?

Accepted Answer

Voltage-gated calcium channels are primarily located at the axon terminal, where they play a crucial role in the release of neurotransmitters.

Question 9

Which of the following best describes the function of the myelin sheath?

Accepted Answer

The myelin sheath functions to insulate axons, which reduces the membrane's ion permeability and increases the speed of electrical signal conduction along the nerve cell.

Question 10

At the resting membrane potential, the membrane is most permeable to , which moves the cell due to its electrochemical gradient.

Accepted Answer

At resting membrane potential, the membrane is most permeable to potassium ions (K+), which move out of the cell due to their electrochemical gradient.

Question 11

The direction of change in membrane potential, in response to a stimulus that initiates a graded potential, is dependent upon

Accepted Answer

The direction of change in membrane potential during a graded potential depends on which ion channels are opened or closed, as this determines the flow of ions across the membrane and thus the change in membrane potential.

Question 12

Which of the following potentials has an all- or- none response?

Accepted Answer

Action potentials have an all-or-none response, meaning that once a certain threshold is reached, the neuron will fire at its full strength or not fire at all. Graded potentials, on the other hand, vary in size and do not have a fixed threshold.

Question 13

A group of nerve cell bodies in the peripheral nervous system are referred to as

Accepted Answer

A group of nerve cell bodies in the peripheral nervous system are referred to as ganglia.

Question 14

The brain and spinal cord are part of which of the following branches of the nervous system?

Accepted Answer

The brain and spinal cord are part of the central nervous system, which consists of the brain, spinal cord, and serves as the control center for the body's nervous system.

Question 15

An action potential originates at the _ and travels along the axon until it reaches the .

Accepted Answer

An action potential typically originates at the axon hillock, which is the region where the axon joins the cell body, and travels along the axon to the axon terminal, where it can trigger the release of neurotransmitters.

Question 16

Toward the end of the relative refractory period, the continued decrease in stimulus intensity required to initiate an action potential is caused by

Accepted Answer

During the relative refractory period, the membrane is returning to its resting state, and potassium channels are closing, leading to decreased potassium permeability. This makes it easier for a subsequent stimulus to reach the threshold and initiate another action potential.

Question 17

At the resting membrane potential, the electrochemical gradient for sodium across the membrane is such that the net flux for sodium movement is directed , thereby causing the cell's membrane potential to become more _ _.

Accepted Answer

At resting membrane potential, the electrochemical gradient for sodium is directed inward, as sodium ions are more concentrated outside the cell. If sodium moves into the cell, it would make the membrane potential more positive.

Question 18

In the peripheral nervous system, myelin is formed by . In the central nervous system, myelin is formed by _ .

Accepted Answer

In the peripheral nervous system, myelin is formed by Schwann cells, while in the central nervous system, myelin is formed by oligodendrocytes.

Question 19

What two divisions of the autonomic nervous system have opposite effects on the organs they innervate?

Accepted Answer

The parasympathetic and sympathetic divisions of the autonomic nervous system have opposite effects on the organs they innervate, with the sympathetic division typically stimulating "fight or flight" responses and the parasympathetic division promoting "rest and digest" activities.

Question 20

What nervous system is found in the intestinal tract?

Accepted Answer

The enteric nervous system is a part of the autonomic nervous system and is specifically located in the gastrointestinal tract, where it controls digestion and gut function.

Quiz 7: Nerve Cells and Electrical Signaling