Lecture 10 - Neurones and Action Potentials

These flashcards cover key concepts related to neurones and action potentials based on lecture notes.

What is the basic structural unit of the nerve system?

The neurone.

What cell types are responsible for myelinating axons in the CNS and PNS respectively?

Oligodendrocytes for CNS and Schwann cells for PNS.

What does the Na-K ATPase pump do?

It pumps three Na+ out of the cell and two K+ into the cell for each molecule of ATP consumed.

What is the typical membrane potential range in most cells?

-50 to -90 mV.

How do action potentials vary in response to stronger stimuli?

A stronger stimulus increases the frequency of action potentials, not their size.

What is the role of neurotransmitters at a synapse?

They are released from the presynaptic terminal, diffuse across the synaptic cleft, and bind to receptors on the postsynaptic membrane.

What is glutamate known for?

It is the major excitatory neurotransmitter that opens Na+ channels to create excitatory post-synaptic potentials (EPSPs).

What is the effect of GABA as a neurotransmitter?

It is the major inhibitory neurotransmitter that opens Cl- channels to create inhibitory post-synaptic potentials (IPSPs).

What process allows multiple EPSPs to trigger an action potential?

Summation.

During an action potential, what phase follows depolarization?

Repolarization.

What is hyperpolarization in relation to action potentials?

It is when the membrane potential becomes more negative than the original resting potential.

Why does the action potential propagate along the axon?

Because depolarization in one part of the membrane triggers neighboring segments to reach the threshold for opening voltage-gated sodium channels.

What structural feature increases the speed of nerve conduction along axons?

Myelin.

What happens to the membrane potential during the depolarization phase of an action potential?

It increases.

How does the cell membrane return to the resting potential after an action potential?

Through the action of sodium-potassium ATPase pumps and potassium leak channels.