Neuro 4

Question 1

graded potentials occur mostly in….

Answer 1

soma

Question 2

action potentials occur mostly in….

Answer 2

axon/axon terminal

Question 3

EPSP …..likelihood of action potential firing

Answer 3

increase

Question 4

IPSP ….likelihood of action potential firing

Answer 4

decrease

Question 5

trigger zone (axon hillock)

Answer 5

~-55 mV

Question 6

AP rising phase

Answer 6

depolarization; open voltage gated Na+ channels and allow Na+ to travel down electrochemical gradient

Question 7

At ….. Na+ channels inactivate

Answer 7

+30mV

Question 8

AP falling phase

Answer 8

repolarization; cottage gated K+ channels open (slower than Na+) causing delayed efflux

Question 9

AP after-hypolarization phase

Answer 9

voltage gated K+ do not immediately close so membrane potential dips below resting membrane potential

Question 10

__________ bring back membrane potential back to -70mV

Answer 10

leak channels

Question 11

inactivation gates ceases a….

Answer 11

positive feedback loop

Question 12

absolute refractory period

Answer 12

all Na+ channel inactivated and a second AP cannot be initiated

Question 13

relative refractory period

Answer 13

a second AP can be initiated, but requires a larger stimulus

Question 14

When positive ions enter neuron (depolarization), current flows to…

Answer 14

adjacent sections of the axon