Nerve Impulse and Transmission Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

When a neuron becomes hyperpolarized, what is the effect on its membrane potential?

The membrane potential becomes less negative than the resting potential

The membrane potential becomes more negative than the resting potential (correct)

The membrane potential remains unchanged

The membrane potential returns to zero

What is the main function of sodium-potassium pumps in neurons?

To maintain a uniform ion concentration outside the neuron

To increase intracellular calcium levels

To regulate the resting membrane potential (correct)

To generate nerve impulses directly

Which ions are primarily responsible for the polarization of a nerve cell's membrane?

Potassium (K+) and Sodium (Na+) (correct)

Chloride (Cl-) and Phosphate (PO4-2)

Bicarbonate (HCO3-) and Sulfate (SO4-2)

Calcium (Ca2+) and Magnesium (Mg2+)

What role do voltage-gated channels play in the transmission of a nerve impulse?

They open in response to changes in membrane potential Signup and view all the answers

What occurs when the membrane potential decreases from the resting state?

The cell undergoes depolarization Signup and view all the answers

What is the resting membrane potential value for a typical nerve cell?

-70 millivolts Signup and view all the answers

Which of the following best describes the term 'membrane potential'?

The electrical charge difference across a nerve cell's membrane Signup and view all the answers

What primarily contributes to the negative resting membrane potential in neurons?

More potassium leakage channels than sodium channels Signup and view all the answers

What role does the sodium potassium pump play in maintaining resting membrane potential?

It brings two K+ ions into the cell while removing three Na+ ions Signup and view all the answers

What happens to the membrane potential when an action potential is triggered?

Potassium channels open after sodium channels to repolarize the membrane Signup and view all the answers

What defines a threshold stimulus in neurons?

A stimulus capable of producing action potential in the neuron Signup and view all the answers

How long does it typically take for a neuron to return to its resting state after an action potential?

10 to 30 milliseconds Signup and view all the answers

What happens to chloride ions (Cl-) in relation to the interior of the cell?

They tend to accumulate outside of the cell due to repulsion Signup and view all the answers

During the depolarization phase of an action potential, what primarily occurs?

Sodium ions rapidly enter the cell through open sodium channels Signup and view all the answers

Which statement about ion movement in neurons is true?

More cations leave the cell than enter it Signup and view all the answers

Study Notes

Hyperpolarization

Hyperpolarization refers to a change in the membrane potential of a neuron making it more negative.
This makes the neuron less likely to fire an action potential.

Sodium-Potassium Pump

The sodium-potassium pump actively transports sodium ions out of the neuron and potassium ions into the neuron.
This maintains the concentration gradients of these ions, which are crucial for the generation of action potentials.

Polarization of a Nerve Cell

The polarization of a nerve cell's membrane is primarily due to the unequal distribution of ions across the cell membrane.
The interior of the cell is typically more negative compared to the exterior due to the presence of negatively charged proteins and a higher concentration of potassium ions inside the cell.

Voltage-Gated Channels

Voltage-gated channels are specialized protein channels in the neuron's membrane that open or close in response to changes in the membrane potential.
They play a crucial role in the transmission of nerve impulses by allowing the rapid inflow or outflow of specific ions, contributing to the depolarization and repolarization phases of an action potential.

Decreasing Membrane Potential

When the membrane potential decreases from the resting state, the neuron becomes less polarized.
This can be caused by an influx of positively charged ions, such as sodium.

Resting Membrane Potential

The resting membrane potential of a typical nerve cell is around -70 millivolts (mV).
This negative value is maintained by the sodium-potassium pump and the selective permeability of the cell membrane to different ions.

Membrane Potential

Membrane potential refers to the electrical potential difference across the cell membrane of a neuron.
It is a measure of the relative charge difference between the inside and outside of the cell.

Negative Resting Potential

The negative resting membrane potential in neurons is primarily due to the presence of negatively charged proteins inside the cell and the selective permeability of the cell membrane, allowing potassium ions to leak out more easily than sodium ions.

Sodium-Potassium Pump and Resting Potential

The sodium-potassium pump contributes to maintaining the resting membrane potential by actively pumping three sodium ions out of the cell for every two potassium ions pumped in.
This process consumes energy and helps to establish and maintain the concentration gradients of these ions, contributing to the negative charge inside the cell at rest.

Membrane Potential During Action Potential

When an action potential is triggered, the membrane potential rapidly rises to a positive value as sodium ions enter the cell, and then drops back down to a negative value as potassium ions leave the cell.
This process is driven by the opening and closing of voltage-gated sodium and potassium channels.

Threshold Stimulus

A threshold stimulus is the minimum level of stimulation required to trigger an action potential in a neuron.
This threshold is typically around -55 mV, and it represents the point at which the depolarization is sufficient to open enough voltage-gated sodium channels to create a positive feedback loop.

Returning to Resting State

It typically takes a few milliseconds for a neuron to return to its resting state after an action potential.
This recovery is due to the inactivation of sodium channels, the opening of potassium channels, and the activity of the sodium-potassium pump.

Chloride Ions (Cl-)

Chloride ions (Cl-) are generally more concentrated outside the cell compared to the interior during the resting state.
They have a role in maintaining the electrical charge balance across the membrane, but their movement during action potentials is less significant compared to sodium and potassium ions.

Depolarization Phase

The depolarization phase of an action potential is characterized by the influx of sodium ions into the neuron.
This influx creates a rapid rise in the membrane potential, making the interior of the cell more positive.

Ion Movement in Neurons

The movement of ions across the neuronal membrane is crucial for the generation and transmission of nerve impulses.
The sodium-potassium pump maintains the concentration gradients of sodium and potassium ions, while voltage-gated channels allow for the rapid influx and efflux of these ions during action potentials.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on nerve impulses, their generation, and transmission through neurons. This quiz covers key concepts such as ion distribution, membrane potential, and the role of voltage-gated ion channels. Perfect for biology students looking to reinforce their understanding of cellular communication.