Neurophysio 1

Question 1

at equilibrium there is _____ ___ ____

Answer 1

no net movement

Question 2

Na+ wants to flow ____

Answer 2

in

Question 3

K+ wants to flow ____

Answer 3

out

Question 4

Cl- wants to flow ___

Answer 4

in

Question 5

concentration gradient is a little ____ than electrical pull

Answer 5

stronger

Question 6

____ ____: the membrane potential when there is a balance between electrical and chemical forces

Answer 6

equilibrium potential

Question 7

assumption of the equilibrium potential: ____ type of ion can diffuse across the membrane at a time

Answer 7

1

Question 8

each ion has its ____ equilibrium potential based on ____ ____ and ___ ___

Answer 8

ionic concentration

electrical charge

Question 9

equilibrium potential predicts:

• ___ of ionic flow
• ___ ____

Answer 9

direction

driving force

Question 10

___ ___: power of the electrical current; stronger the currect, the faster the flow

Answer 10

driving force

Question 11

equilibrium potential has 2 other names

Answer 11

reversal potential

nernst potential

Question 12

___ ___: when there is only 1 ion affecting membrane potential; point at which the polarity of the membrane potential switches

Answer 12

reversal potential

Question 13

most of the cells resting membrane potential is determined by the equilibrium for ____

Answer 13

POTASSIUM

Question 14

equilibrium potential ranges from ___ to ___

Answer 14

-65 to -95

Question 15

resting membrane potential is predicted by the ___ ___ ___ equation

Answer 15

goldman hodgkin katz

Question 16

GHK found that resting membrane potential is related to the concentration of ____ of the 3 ions and the cells ___ to each

Answer 16

each

permeability

Question 17

equation for driving force= _____ - _____

Answer 17

resting membrane potential MINUS equilibrium potential for the ion

Question 18

the larger the driving force, the ___ the ionic current will travel once the cell becomes permeable to that ion

Answer 18

faster

Question 19

___ channels: responsible for resting membrane potential

Answer 19

leaky channels

Question 20

__ ___ channels: responds to neural transmission; post synaptic side; neuron communicates

Answer 20

ligand gated

Question 21

___ ____ channels: responsible for the generation of APs

Answer 21

voltage gated

Question 22

changes in membrane potential affect the properties ___ ___ ion channels causing them to open or close

Answer 22

voltage gated

Question 23

___: changing the state of these channels allows for ionic flow into and out of the neuron

Answer 23

current

Question 24

___ ____ ___: the flow into the cell leads to depolarization and further AP regeneration along the neuronal axon, repeating until it reaches the terminal

Answer 24

positive feedback loop

Question 25

2 mechanisms that allow ionic flow across the channel

Answer 25

ligand gated | voltage gated

Question 26

___ ___ potential: more positive charge in the cell than before

Answer 26

excitatory postsynaptic potential

Question 27

EPSP are controlled by the small influx of ___

Answer 27

Na+

Question 28

____ ___ potential: makes it harder to generate an action potential

Answer 28

inhibitory postsynaptic potential

Question 29

___ in the membrane prevents EPSPs from sticking around

Answer 29

leakage

Question 30

if EPSPs are summed to threshold, a spike is ____

Answer 30

generated

Question 31

reaching the ___ potential leads to a massive depolarization

Answer 31

threshold

Question 32

a voltage gated Na+ channel contains a ___ charge

Answer 32

positive

Question 33

when there is a large enough change in membrane charge, the voltage gated Na+ channel will change conformation and ____

Answer 33

open

Question 34

voltage gated ion channels are located in ___

Answer 34

clusters

Question 35

when threshold is reached in one area, it causes a ___ ____ and ___ is reached in adjacent areas; this is the ____ property of an AP

Answer 35

local depolarization threshold regenerative

Question 36

APs happen in an ____ or ____ way

Answer 36

all | nothing

Question 37

voltage gated Na+ channels inactivate quickly via ___ ___ ___ mechanism

Answer 37

ball and chain

Question 38

when the membrane potential is too depolarized, the voltage gated Na+ channel's own side chain ___ the open pore

Answer 38

plugs

Question 39

voltage gated K+ channels work like voltage gated Na+ channels but they are _____

Answer 39

slower

Question 40

voltage gated K+ only open after the cell has depolarized so much that the membrane potential is close to ___mV

Answer 40

30

Question 41

when the cell gets to 30mV there is a huge flow of K+ ___ to reestablish membrane potential

Answer 41

out

Question 42

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

Answer 42

afterhyperpolarization

Question 43

when the cell detect that afterhyperpolarization occurs, _____ ___ begins to work to increase intracellular Na+ concentrations

Answer 43

Na+/K+/ATPase pump

Question 44

____ ___ period: voltage gated Na+ channels will not open temporarily, regardless of stimulus; another AP cannot be regenerated

Answer 44

absolute refractory

Question 45

___ ___ period: while voltage gated K+ channels have opened, the driving force of K+ to leave the cell is much stronger than the driving force for Na+ to enter the cell; it is possible to elicit another AP with a strong enough influx of Na+

Answer 45

relative refractory period

Question 46

____: the degree to which ion channels are open for a given area on the cell membrane

Answer 46

conductance

Question 47

changing either the number of channels open or the openness of individual channels will change ___ ___

Answer 47

ionic current

Question 48

conductance is the invers of ____

Answer 48

resistance

Question 49

Ohm's Law _=__x___

Answer 49

voltage (V) = current (I) x resistance (R)

Question 50

resistance affects current across 2 directions

Answer 50

across the membrane | across the cytoplasm

Question 51

if there is ____ resistance in the membrane that there is in the cytoplasm, the current will tend to flow through the _______ rather than leaking back out

Answer 51

greater | cytoplasm

Question 52

as diameter of an axon ____, there is more cytoplasm to flow through instead of back through the membrane.

Answer 52

increases

Question 53

the bigger axons conduct with ___ velocity

Answer 53

higher

Question 54

the ____ the axon, the more area it has for ions to flow in, the ____ the action potential is regenerated

Answer 54

fatter | faster

Question 55

myelinated axons conduct action potential much ___ than unmyelinated axons

Answer 55

faster