ion chsnnels and action potential in neurons

Question 1

what are ion channels

Answer 1

protein complexes spanning the length of the membrane that act as channels/transporters that allow rapid flow of selected ions

Question 2

describe how the different types of ion channels are gated

Answer 2

voltage-gated ion channels(VGIC), membrane potential
ligand-gated ion channels(LGIC), chemical substances
physical stimuli(eg thermal, mechanical)

Question 3

describe what ion channels are responsible for membrane potential in neurons and how the Na+ and K+ channels are gated

Answer 3

ion channel = voltage-gated ion channels|(VGIC)
voltage-gated Na+ channels opened by depolarisation
voltage-gated K+ channels opened by hyperpolarisation

Question 4

describe what action potentials in neurons are

Answer 4

action potentials = brief electrical signals in which the polarity of the nerve cell membrane is momentarily reversed

Question 5

what part of the neuron does action potential occur at and describe the magnitude and velocity of action potentials

Answer 5

occurs along axon of neurons

magnitude and velocity are constant, allows signalling over long distance

Question 6

when are action potentials generated

Answer 6

when threshold of membrane potential(~60mV) is reached