Electrical Neural Signalling

Question 1

anions

Answer 1

negatively charged ions

Question 2

ion channel

Answer 2

a tubelike pore that allows ions of a specific type (K+) to pass thought the membrane

Question 3

diffusion

Answer 3

molecules tend to move down their concentration gradient until they are evenly distributed

Question 4

Action potential

Answer 4

very brief but large changes in neuronal polarization that arise in the initial segment of the axon and are propagated at high speed along the axon’s length

Question 5

Hyperpolarization

Answer 5

increasing negativity of the membrane potential (farther from zero)

Question 6

Depolarization

Answer 6

decreased polarization of the cell membrane

Question 7

voltage-gated Na+ channel

Answer 7

includes a tubular, membrane-spanning protein, but this Na+-selective pore is ordinarily closed. This is really quite a complicate machine -> it monitors the axon’s polarity and at threshold it changes its shape to open the channel, shutting down again just a millisecond later.

Question 8

saltatory conduction

Answer 8

The myelin sheath that encases some axons is interrupted by nodes of Ranvier -> the action potential jumps from node to node

Question 9

Equilibrium potential

Answer 9

the electrical potential at which a given concentration gradient across the membrane is stable, when the membrane is permeable for x.