Neurophys: Action Potential

Question 1

Def of depolarization

Answer 1

Undo / taking away polarization

Question 2

Outside (depol.)

Answer 2

Negative
-More Na+ (salty on the outside)

Question 3

Inside (depol.)

Answer 3

Positive
-More K+
-Na moving in bc soDium is being Deeepolarized

Question 4

K+ (depol.)

Answer 4

Potassium
-Travels outside (-)
-Gated/closed =slow

Question 5

Na+ (depol.)

Answer 5

Sodium
-Goes IN (+++)
-leakage and voltage = open all the way
-being Deeeeeepolarized

Question 6

Repolarization

Answer 6

Being polarized again/Doing it again
-Out (+++)
-Inside (- - -)

Question 7

Na (Repol)

Answer 7

Sodium is going in through leakage
-Voltage = flap opens to outsid, closed on inside

Question 8

K (repol)

Answer 8

Potassium is being rePolarized
-goes out in leakage
-Voltage is open

Question 9

Hyperpolarization

Answer 9

Extra polarized

Question 10

Na (hyper)

Answer 10

Sodium is going in through leakage
-Voltage is fully closed

Question 11

K (hyper)

Answer 11

Potassium is going out through leakage
-Voltage is starting to close/half way open

Question 12

Na (rest)

Answer 12

-going in
-Voltage flap on inside is open

Question 13

K (rest)

Answer 13

-Goes out
-Voltage is closed

Question 14

Graded potentials

Answer 14

-short-distance and short-lived
• depolarizations or hyperpolarizations
• occur when a stimulus causes gated ion channels to open

Question 15

Absolute refractory period

Answer 15

-Time from the opening of the Na+
channels until they begin to reset
• Ensures that each AP is an all-or-none
event (NO new AP)
• Enforces one-way transmission of nerve
impulses

Question 16

Relative refractory period

Answer 16

Follows the absolute refractory period
– Most Na+ channels are closed again
– Some K+ channels are still open
– Repolarization is occurring
• Threshold for AP generation is elevated
• Exceptionally strong stimulus may
generate an AP —> relatively difficult

Question 17

Voltage gated channels

Answer 17

Open and close in response to changes in membrane potential