Question 1

The minimum length of time between action potentials is determined by

Accepted Answer

The minimum length of time between action potentials is determined by the absolute refractory period, which is a brief period after a neuron fires an action potential during which it is unable to fire another one. This is due to the inactivation of sodium channels that occurs after an action potential is fired, which must be reset before another action potential can be generated. The other choices, transduction capacity and incapacity, and relative threshold period, are not relevant to determining the minimum length of time between action potentials.

Question 2

Fiona puts her hands into a sinkful of lukewarm water; Luke puts his hands into a sinkful of ice-cold water. Based on what is known about neural transmission, you could predict that the action potentials will

Accepted Answer

The all-or-none principle states that a neuron either fires an action potential or does not, regardless of the intensity of the stimulus. Therefore, the action potentials will be the same in both individuals. The temperature of the water in which their hands are submerged should not have any significant impact on the speed or intensity of neural transmission.

Question 3

The process by which neural impulses are transmitted through the nervous system is best described as

Accepted Answer

Neural impulses are transmitted through the nervous system by a combination of electrical and chemical signals, making the process best described as electrochemical in nature. Electrical signals (action potentials) travel down the length of the neuron to the axon terminal, where the release of neurotransmitters (chemicals) allows the signal to be transmitted to the next neuron or target cell.

Question 4

The neurons in Michael's arm just sent a neural impulse. It will be 1-2 milliseconds before another neural impulse can be generated. This brief time period, when another neural impulse cannot occur, is called the

Accepted Answer

The absolute refractory period is the brief time period after a neural impulse where another impulse cannot occur. The other answer options are not relevant to the situation described in the scenario.

Question 5

When a neuron's electrical charge becomes positive and travels along the axon, the neuron is said to be firing

Accepted Answer

When a neuron's electrical charge becomes positive and travels along the axon, it is called an action potential, which is the electrical impulse that travels along the neuron's axon. The resting potential refers to the neuron's state when it is not firing, and a chemical potential is not directly related to the electrical activity of a neuron.

Question 6

If action potentials follow the all-or-none principle how is it possible for us to distinguish between different levels of stimulus intensity?

Accepted Answer

The rate at which action potentials are fired (option B) can be used to distinguish between different levels of stimulus intensity. Additionally, different neurons may transmit signals at different speeds (option C), which can also help the brain distinguish between different levels of stimuli. Therefore, both options B and C are correct.

Question 7

Comparing a neuron to a gun that holds only a single bullet, the time it takes to reload the gun is similar to the neuron's

Accepted Answer

The absolute refractory period is the period of time after a neuron fires an action potential during which it cannot fire another one, no matter how strong the incoming signal. This is similar to the way a gun cannot be fired immediately after it is shot, as it takes a certain amount of time to reload.

Question 8

When a neuron is at its resting potential it has

Accepted Answer

When a neuron is at its resting potential, it has a stable negative charge. This means that the inside of the neuron is negatively charged relative to the outside. The resting potential is usually around -70 millivolts.

Question 9

The typical speed of an action potential is

Accepted Answer

The typical speed of an action potential is between 2 and 200 miles per hour. It can vary depending on factors like axon diameter and myelination, but it is generally much slower than the speed of light or sound. The intensity of excitatory signals can affect the frequency of action potentials, but not their actual speed.

Question 10

After firing an action potential a neuron

Accepted Answer

After firing an action potential, a neuron enters a refractory period during which it cannot immediately fire another action potential. This period ensures that action potentials only travel in one direction along the neuron and allows the neuron to reset its ion channels.

Question 11

Action potentials

Accepted Answer

Action potentials are generated in an all-or-none fashion, meaning they either occur fully or not at all. The strength of the incoming stimulation affects the frequency of action potentials, not their amplitude or size. Action potentials also travel at a constant speed regardless of the intensity of the incoming stimulation.

Question 12

The electrical charge inside a neuron when it is in its resting state is approximately

Accepted Answer

The electrical charge inside a neuron when it is in its resting state is approximately -70 millivolts, which is represented as -70mV. This is due to the presence of a higher concentration of negatively charged ions inside the cell and positively charged ions outside the cell, creating a potential difference across the cell membrane. This potential difference is known as the resting membrane potential. Option A and C are not correct because the value of electrical charge in volts is much higher than what is observed in the resting state of a neuron. Option B is also not correct because the value is too low.

Question 13

Leonard's mother became dehydrated during a recent illness, and the levels of sodium in her body were significantly reduced. If enough sodium was lost you might expect that

Accepted Answer

Sodium is essential for proper nerve function and for generating action potentials. If sodium levels in the body are reduced, there may not be enough sodium available to generate as many action potentials as usual, resulting in fewer action potentials occurring in the nervous system.

Question 14

As a neuron is stimulated and starts to receive information the neuron's electrical charge

Accepted Answer

When a neuron is stimulated and starts to receive information, it becomes less negative. This occurs because the stimulation causes positively charged ions to flow into the neuron, making its electrical charge less negative. This change in electrical charge is known as depolarization and is the first step in the process of a neuron firing an action potential.

Question 15

When a neuron is firing its action potential the neuron's electrical charge is

Accepted Answer

When a neuron is firing its action potential, the neuron's electrical charge becomes briefly positive inside the axon and negative outside the axon. This positive charge travels along the axon, which is the long, slender projection of the neuron that carries the nerve impulse away from the cell body towards other neurons, muscles, or glands.

Question 16

Peggy smells a very strong odor; Harry smells an odor that is barely detectable. Based on what is known about neural transmission you could predict that the action potentials will

Accepted Answer

The answer of Peggy smells a very strong odor; Harry...

Question 17

An action potential is

Accepted Answer

An action potential is an electrical signal that travels along the axon of a neuron. It is initiated by the opening of voltage-gated ion channels, which causes a change in the membrane potential and triggers the movement of ions down the axon. This process creates a wave of depolarization that allows the action potential to propagate down the length of the axon, ultimately leading to the release of neurotransmitters at the synapse.

Question 18

If a neuron is not receiving any input or information, the neuron is at its

Accepted Answer

When a neuron is not receiving any input or information, it is said to be at its resting potential. This is the state in which the neuron is not actively sending or receiving messages and is essentially "at rest." This resting potential is maintained by the balance of ions (charged particles) inside and outside of the neuron's cell membrane.

Question 19

Neurotransmitters are secreted from the

Accepted Answer

Neurotransmitters are secreted from the terminal buttons, which are located at the end of the axon and communicate with other neurons or target cells. Myelin sheath is a fatty covering that surrounds and insulates axons. Neuromodulators are chemicals that affect the activity of neurotransmitters. Dendrites are branching extensions of neurons that receive signals from other neurons.

Question 20

Sara is holding Scott's hand during a scary movie. Suddenly she squeezes his hand very hard. When she does this, the neurons in Scott's hand will

Accepted Answer

When Sara squeezes Scott's hand very hard, the neurons in his hand will start to fire at a faster rate. This is because the increased pressure on the hand stimulates the sensory receptors, which in turn activate the neurons that carry the signals to the central nervous system. The increased firing rate indicates a stronger signal being sent to the brain, but it is not necessarily related to the release of chloride ions or the absolute refractory period.

Quiz 5: The Biological Bases of Behavior Part 1