membrane potential

Question 1

leakage channels

Answer 1

randomly alternating b/w open and closed positions

Question 2

voltage-gated channels

Answer 2

open/close in response to change in membrane potential (voltage)

Question 3

ligand-gated channels

Answer 3

open/close in response to specific chemical stimulus

Question 4

mechanically-gated channels

Answer 4

open/close in response to mechanical stimulation

Question 5

light-gated channels

Answer 5

open/close in response to light entering retina

Question 6

resting membrane potential

Answer 6

build-up of negative ions in the cytosol along inside of membrane, and positive ions in extracellular fluid along outside of membrane

• ranges from 40 to -90 mV; typically -70 mV

Question 7

graded potential

Answer 7

slightly more polarized (more negative inside) or less polarized (less negative inside)

• occur in dendrites or cell body

Question 8

depolarizing phase

Answer 8

Na+ enter and makes cell more positive

Question 9

repolarizing phase

Answer 9

Na+ channels close and K+ channels slowly open

Question 10

calcium

Answer 10

plays major role in chemical synapse

Question 11

potassium K+

Answer 11

stabilize resting potential

Question 12

sodium Na+

Answer 12

initiate action potential (depolarization)

Question 13

saltatory conduction

Answer 13

special mode of impulse propagation along well-myelinated axons

Question 14

continuous conduction

Answer 14

step-by-step depolarization and repolarization of adjacent segments of plasma membrane