3. Action Potentials I

Question 1

large, rapid changes in membrane potential

Answer 1

action potentials

Question 2

produced by excitable cells, like neurons and muscle cells in response to stimuli

Answer 2

action potentials

Question 3

graded potentials are induced in 2 places

Answer 3

dendrites and cell body

Question 4

dendrites receive neurotransmitters from other neurons and respond by producing small, localized changes in membrane potential

Answer 4

graded potentials

Question 5

what do graded potentials do?

Answer 5

regulate action potential production @ the initial segment

Question 6

Where are action potentials induced? what happens after this and what does it stimulate?

Answer 6

initial segment; it is propagated along the axon to each axon terminal, where it stimulates the release of neurotransmitters.

Question 7

graded potentials are also known as

Answer 7

postsynaptic potentials

Question 8

the cell body is AKA

Answer 8

soma

Question 9

presynaptic terminal is aka

Answer 9

axon terminal

Question 10

spike initiation zone is aka

Answer 10

initial segment

Question 11

Every action potential produced by a particular cell is ________, showing the same changes in mem potential and same duration

Answer 11

identical

Question 12

Action potentials have an ______________________________ response to a stimulus= it either produces an action potential or it doesn’t. Once it starts it can’t stop

Answer 12

all-or-none

Question 13

action potentials are _________ __________ __________, meaning that the ap that occur at the axon terminals are identical to the one induced at the initial segment

Answer 13

transmitted without decrement

Question 14

what is the typical resting potential for neurons?

Answer 14

-70 mV

Question 15

A change in membrane potential to a less negative value than the resting potential. (-70mV changing to -50mV or +10mV)

Answer 15

depolarization

Question 16

a change in mem pot to a more negative value than the resting potential (-70 to -90)

Answer 16

hyperpolarization

Question 17

A return to the resting potential from a depolarized state (-50 to -70)

Answer 17

repolarization

Question 18

Which gates are closed when a voltage-gated Na+ channel is in the inactivated state?

Answer 18

The inactivation gates only

Question 19

The last of the voltage-gated K+ channels do not enter the closed state until

Answer 19

The end of the undershoot phase

Question 20

K+ leak channels are open during an action potential (true or false(

Answer 20

True

Question 21

During the depolarization phase, the membrane is less permeable to Na+ than it is to K+ (t or f)

Answer 21

True

Question 22

If the membrane potential were -40mV, which of the following changes in membrane potential would be a hyper polarization?
-20 to -40
-40 to -70
-40 to -30
-60 to -40

Answer 22

Change from -40 to -70 mV

Question 23

If the resting potential were -80 and the threshold potential were -60, which of the following depolarizations would be a threshold potential?

Answer 23

+20 mV

Question 24

A voltage-gated Na+ channel can open in response to a hyper polarization (t or f)

Answer 24

True

Question 25

The Hodgkin cycle is terminated by

Answer 25

The closing of the inactivation gate

Question 26

K+ permeability during the undershoot phase is the same as the K+ permeability during the resting potential (t or f)

Answer 26

False

Question 27

The inactivation gate is closed during the undershoot phase (t or f)

Answer 27

False