chapter 15

Question 1

what causes depolarisation

Answer 1

stimulus causes sodium ion channels to open and sodium ions diffuse into the axon

Question 2

what causes the membrane to be depolarised

Answer 2

sodium ions channels close
potassium ions channels and they diffuse out of axon

Question 3

what causes hyperpolarisation

Answer 3

potassium channels are slow to close so too many potassium ions diffuse out

Question 4

describe how a resting potential is maintained

Answer 4

the sodium potassium pump actively transports sodium ions out and potassium ions in (3 Na+/ 2 K+)

potassium ions channels open so potassium ions diffuse out

sodium channels close and sodium ions can’t diffuse in