Action Potential and Nerve Impulses

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Questions and Answers

What causes the outer surface of the membrane to become negatively charged during nerve impulse generation?

Depolarization

Influx of K+ ions

Reversal of polarity

Rise in permeability to Na+ ions (correct)

What is the term used to describe the electrical potential difference across the plasma membrane at the site where depolarization occurs?

Action potential (correct)

Nerve impulse

Resting potential

Polarizing potential

What is the direction of current flow on the inner surface of the axon membrane from site A to site B?

Current does not flow on the inner surface

Both sites have equal current flow

From site B to site A

From site A to site B (correct)

Which ion diffusion helps restore the resting potential of the membrane at the site of excitation after nerve impulse generation?

K+ ions Signup and view all the answers

What happens to the polarity of the membrane at site B during nerve impulse conduction?

It reverses similar to site A Signup and view all the answers

Which term is synonymous with depolarization during nerve impulse generation?

Excitation phase Signup and view all the answers

What is the main function of the sodium-potassium pump mentioned in the text?

Transport 3 Na+ outwards and 2 K+ into the cell Signup and view all the answers

What is the role of the concentration gradient across the axonal membrane?

Help generate nerve impulses Signup and view all the answers

What term is used to describe the electrical potential difference across the resting plasma membrane?

Resting potential Signup and view all the answers

How does the membrane at the site A become when a stimulus is applied?

Freely permeable to Na+ Signup and view all the answers

What happens to the inner surface of the axonal membrane during polarization?

Becomes negatively charged Signup and view all the answers

Which process involves transporting more Na+ out of the cell than K+ into the cell?

Action potential Signup and view all the answers

Why are neurons considered excitable cells?

Due to the selective permeability of ion channels on the neural membrane Signup and view all the answers

Which type of nerve fibre is commonly found in autonomous and somatic neural systems?

Unmyelinated nerve fibre Signup and view all the answers

During resting state, which ion is the axonal membrane more permeable to?

Potassium ions (K+) Signup and view all the answers

What is the function of nodes of Ranvier?

To allow for saltatory conduction along myelinated nerve fibres Signup and view all the answers

What does it mean for a neuron membrane to be in a polarised state?

The membrane has selective permeability to different ions Signup and view all the answers

Which type of neuron has one axon and two or more dendrites, typically found in the cerebral cortex?

Multipolar neuron Signup and view all the answers

Study Notes

Nerve Impulse Generation

The outer surface of the membrane becomes negatively charged during nerve impulse generation due to the movement of potassium ions (K+) out of the cell, leaving behind negatively charged ions.
The electrical potential difference across the plasma membrane at the site where depolarization occurs is termed the action potential.
The current flow on the inner surface of the axon membrane from site A to site B is from the positive to the negative charge due to the influx of sodium ions (Na+).
The diffusion of potassium ions (K+) helps restore the resting potential of the membrane at the site of excitation after nerve impulse generation.
The polarity of the membrane at site B becomes depolarized during nerve impulse conduction, meaning the inside becomes less negative.
The term depolarization refers to the process of the membrane potential becoming less negative.
The main function of the sodium-potassium pump is to actively transport three sodium ions (Na+) out of the cell for every two potassium ions (K+) transported into the cell, maintaining the concentration gradients essential for nerve impulse conduction.
The concentration gradient across the axonal membrane is crucial for maintaining the resting potential and generating an action potential.
The electrical potential difference across the resting plasma membrane is termed resting membrane potential.
When a stimulus is applied, the membrane at site A becomes depolarized.
During polarization, the inner surface of the axonal membrane becomes negatively charged while the outer surface is positively charged.
The process of transporting more Na+ out of the cell than K+ into the cell is known as active transport and requires energy expenditure.
Neurons are considered excitable cells because they can generate and transmit electrical signals (action potentials) in response to stimuli.
Myelinated nerve fibers are commonly found in both autonomous and somatic neural systems.
During resting state, the axonal membrane is more permeable to potassium ions (K+) due to the presence of more potassium leak channels.
Nodes of Ranvier are gaps in the myelin sheath that allow for faster conduction of nerve impulses by allowing the action potential to "jump" from node to node.
A neuron membrane in a polarized state signifies a separation of charges across the membrane, with the inside being negative compared to the outside.
A multipolar neuron has one axon and two or more dendrites and is typically found in the cerebral cortex.

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Description

Learn about the process of action potential generation and nerve impulse transmission in neurons. Understand the reversal of polarity across the membrane and the depolarization that occurs during an action potential.