Action Potentials and Neural Communication

These flashcards cover the fundamental concepts of action potentials, neuron structure, and neurophysiology based on the provided lecture notes.

What do sensory neurons in the peripheral nervous system detect?

They detect stimuli such as temperature.

What is a graded potential?

A small, localized change in membrane potential that may or may not lead to an action potential.

What happens if a graded potential reaches the threshold?

It triggers an action potential, which is an all-or-nothing response.

What is the role of the thalamus in sensory processing?

It relays sensory information to the cerebral cortex.

What channels open during depolarization of the membrane?

Voltage-gated sodium channels open, allowing sodium ions to flood into the cell.

What is the typical resting membrane potential of a neuron?

Negative 70 millivolts.

What ion is crucial for muscle contractions?

Calcium.

What are leak channels?

Channels that occasionally open and allow certain ions to pass through, contributing to membrane potential.

What is hyperpolarization?

A state where the membrane potential becomes more negative than the resting membrane potential.

What keeps the resting membrane potential stable?

The sodium-potassium pump, which maintains the concentration gradients of sodium and potassium ions.

What are the two main classes of neurotransmitters?

Excitatory neurotransmitters, which stimulate action, and inhibitory neurotransmitters, which block or reduce activity.

What is saltatory conduction?

A faster form of action potential propagation that occurs in myelinated axons.

What is the function of the sodium-potassium pump?

It exchanges three sodium ions out of the cell for two potassium ions into the cell, maintaining the resting membrane potential.

What is the all-or-nothing principle?

Once the threshold is reached, an action potential will occur; if not reached, no action potential occurs.

What happens during repolarization?

Potassium channels open, and potassium ions leave the cell, returning the membrane potential toward resting levels.

What enzyme degrades acetylcholine in the synaptic cleft?

Acetylcholinesterase.

What is the axon hillock?

The region of the neuron where graded potentials are summed to determine if an action potential will occur.

What type of receptors are ionotropic receptors?

Receptors that are ion channels that open upon binding of their ligand.

What is the role of interneurons in the nervous system?

They process information and determine the response required upon receiving sensory input.

What occurs during the refractory period?

It is a phase after an action potential during which no new action potential can be initiated.