48.3 Action Potentials

Question 1

when neurons are active:

Answer 1

membrane permeability and membrane potential change

no more resting potential

Question 2

why do these changes occur

Answer 2

gated ion channels

in the neurons- open and close ion channels to change membrane potential

Question 3

what happens when gated K+ channels closed in resting neurons open (more K+ channels)

Answer 3

-increase membrane permeability to K+
-increase net diffusion out
-inside gets more (-) approaching -90mV (Ek)
-separation of charge or polarity
-HYPERPOLARIZATION-hyperpolarization
-

Question 4

hyperpolarization

Answer 4

making more (-)

• -decrease + ions or
• -increase - ions

Question 5

depolarization

Answer 5

making more (+)

• -(Na+ gated ion channels open-> Na+ diffuse into cells)
• -

Question 6

what happens when gated sodium ion channels open?

Answer 6

Na+ come in

• DEPOLARIZATION
• membrane potential approaches +62mV (Ena)

Question 7

graded potentials

Answer 7

the magnitude of the change in membrane potential varies with the strength of the stimulus
-are not actual nerve signals, but have a major affect on the generation of nerve signals