Lecture 28 Action Potentials Part 2

Flashcards about Action Potentials: Generation and Transmission

The action potential lasts a few __ in axons.

milliseconds

The action potential lasts a bit longer in .

cell bodies

The action potential is caused by a fluctuation in caused by a transient opening of - ion channels.

membrane potential, voltage-gated

The three key stages of the action potential are fast to about +30mV, and __.

depolarisation, repolarisation, hyperpolarisation

Stage 1 of the action potential is always preceded by a period during which the cell membrane is depolarised to __.

threshold

During the resting membrane potential is much greater than .

PK, PNa

During stage 1, fast depolarisation, is much greater than .

PNa, PK

During stage 2, repolarization, is much greater than .

PK, PNa

During stage 3, after-hyperpolarization, is much greater than and then _ is much greater than _.

PK, PNa, PK, PNa

Myelination of the axon __ the action potential (AP) conduction velocity.

increases

APs are generated only at of .

nodes, Ranvier

Current flows __ between nodes in myelinated axons.

passively

The process by which current flows passively between nodes in myelinated axons is known as .

saltatory conduction

In sensory neurons, a stimulus evokes a graded depolarisation known as the .

receptor potential

The potential spreads passively to the nearby located __ where APs are generated in sensory neurons.

receptor, trigger zone