Action Potential Wk 10/ 11

Question 1

At rest, cells reach balance btw electrical and concentration gradients so there is ______

Answer 1

no net flow

Question 2

Resting membrane potential is usually ___ to ___

Answer 2

-65mV to -95mV

Question 3

resting membrane potential of neurons in the CNS is ______

Answer 3

-70 mV

Question 4

_____: changes in membrane potential that spread across the cell

Answer 4

action potentials

Question 5

Changes in a membrane potential affect the prop’s of _____ion channels

Answer 5

voltage gates

• causes then to open and close

Question 6

positive feedback from a membrane potential causes _____ of the membrane

Answer 6

depolarization

Question 7

Changes in ____ channels affect the properties of the voltage gated channel

Answer 7

ligand chanels

• cause depolarization- the voltage channel feels this change

Question 8

___: when the flow leads to depolarization and further AP regeneration along the neuronal axon, repeats until it reaches terminal

Answer 8

positive feedback loop

Question 9

the opening of a NA+ channel creates a _____ current

Answer 9

Na+ current

Question 10

Na+ will flow according to : (2)

Answer 10

1. resting membrane potential

2. Na+ equilibrium potential

Question 11

EPSP stands for =

Answer 11

Excitatory postsynaptic potential

Question 12

what causes a faster current flow into/out of the cell?

Answer 12

by making the resting membrane potential MORE different than the equilibrium

Question 13

IPSP stands for=

Answer 13

inhibitory postsynaptic potential

Question 14

______ chanels (besides Na+ chanels) can also open in response to ligands

Answer 14

Cl- channels

Question 15

Cl- channels opening in response to ligands will cause _____

Answer 15

hyperpolarization

Question 16

hyperpolarization is caused by ___

Answer 16

cl- channels opening in response to ligands

Question 17

leakage in the membrane prevents ____ from sticking around

Answer 17

EPSPs

excitatory postsynpatic potential

Question 18

Threshold is considered to be ____ to ____ mV

Answer 18

15-20

Question 19

_____: if EPSPs are summed to threshold (15-20 mV above resting potential), a spike is generated

Answer 19

action potential

Question 20

An action potential is when _____ are summed to threshold

Answer 20

EPSPs

15-20mV above resting potential

Question 21

reaching the _____ potential leads to massive depolarization

Answer 21

threshold

Question 22

reaching the threshold potential leads to massive ______

Answer 22

depolarization

Question 23

IPSP summation does what?

Answer 23

takes the membrane potential away from reaching threshold

Question 24

A voltage gated ____ channel contains a region with a (+) charge

Answer 24

Na+

Question 25

When there is a large enough threshold change what occurs?

Answer 25

there is a change in conformation and the channel opens

Question 26

_______: is a property where a threshold is reached in one area, it causes local depolarization and threshold to be reached in adjacent areas

Answer 26

regenerative property (wave-like)

Question 27

explain regenerative property

Answer 27

it is when the threshold is reached in one area, it causes local depolarization and threshold to be reached in adjacent areas

Question 28

action potentials are ___ or __

Answer 28

all or none

Question 29

What are action potentials all or none?

Answer 29

regenerative property: when the threshold is reached in one area, it causes local depolarization and threshold to be reached in adjacent areas

Question 30

voltage-gated Na+ channels inactivative quickly via _______ mechanis,

Answer 30

ball and chain

Question 31

When the membrane potential is too depolarized , the channel's __________

Answer 31

own peptide side chain plugs up the opening of the pore

Question 32

What plugs up the opening of the pore when the membrane potential is too depolarized

Answer 32

its own peptide side chain

Question 33

____ woltage gated channels are "slower"

Answer 33

K+

Question 34

_____ channels only opening after the cell has depolarize so much that the membrane potential is close to 30 mV

Answer 34

K

Question 35

_____ channels only open after the cell has overshoot and depolarized

Answer 35

K

Question 36

K+ equilibrium potential

Answer 36

-90mV

Question 37

K+ flowing out causes the cell membrane to ____

Answer 37

repolarize

Question 38

What occurs at "afterhyperpolarization"

Answer 38

so much K+ flows out od the cell that the cell is at an even lower membrane potential than at rest

Question 39

________ begins working when it senses an increase in intracellular Na+concentrations

Answer 39

Na/K/ ATPase pump

Question 40

When does the Na/K/ ATPase pump being to work?

Answer 40

when it sense and increase in intracellular Na+ concentration

Question 41

the activity of ______ helps to being the cell back to resting potential again

Answer 41

Na/K/ATPase

Question 42

Na+ channels open during ___ to ____mV. They close at ____mV

Answer 42

open -70mV - +30mV close: +30 mV Na+ is positive so it moves more positive

Question 43

The Na+/K+ pump become after _____

Answer 43

"after hyperpolarization"

Question 44

Voltage-gates Ca2+ channels contribute to the ____ phase

Answer 44

deparolarization phase

Question 45

carbic action potential has a inward current of ____ & ___ and an outward current of ____

Answer 45

inward: Na+ and Ca+ outward: K+

Question 46

In neurons, voltage gates __ channels are used in vesicle binding and release of neurotransmitters

Answer 46

Ca2+

Question 47

Ca+2 voltage gates are used for _______ & ______ in neurons

Answer 47

vesicle binding and release of neurotransmitters

Question 48

in muscles action potentials cause _____

Answer 48

muscle contractions

Question 49

In neurons action potentials cause: ______

Answer 49

vesicles to fuse and release neurotransmitters

Question 50

_____ is the point at which another action potential cannot be generated

Answer 50

absolute refractory period

Question 51

_________: when the voltage gates Na channels will not open temporarily, regardless of stimulus strength

Answer 51

absolute refractory period

Question 52

What occurs during relative refractory period

Answer 52

voltage gate K - force K+ to leave the cell is stronger than the Na+ force to enter the cell

Question 53

_______: when the driving force of K+ to leave the cell is stronger than the driving force for Na+ to enter the cell

Answer 53

relative refractory period

Question 54

During _______, it is impossible to elicit another action potential

Answer 54

relative refractory period