1. Neurophysio Part 1 : electrical props and AP Flashcards Preview

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Flashcards in 1. Neurophysio Part 1 : electrical props and AP Deck (54):
1

_____ are made in the cell and located intracellularly. They produce a more neg charge in the cell

protein

2

There is ______ NRG created from the chem conc gradient

potential nrg

3

________: the membrane potential when there is a balance btw electrical and chem forces

equilibrium potential

4

What are two effects that equilibrium potential is dependent on

1. intra/extrcellular ionic concentration
2. electrical charge of ion

5

equilibrium potential predicts (2)

1. direction of ionic flow
2. DRIVING FORCE

6

the loss of K+ results in a ____ charge on the inner plasma membrane face

negative charge

7

______: when there is only 1 ion affecting membrane potential

reversal potential

8

Equil potential for K+ is ______mV

-87mV

9

** most of the cells RMP is determined by the equil potential for ____

K+

(Bc of the leaky K+ channels )

10

RMP values for most cells range from ___ to ___mV

-65mV to -95mV

11

RMP is related to the conc. of what three ions

Na+, K+, and Cl-

12

According to GHK, RMP is related to what 2 factors?

conc gradient of ions (Na+, K+, Cl-)

cells permeability to each

13

at RMP the cell is ___x more permeable for K than other ions

1000s

14

What are the two major forces acting on the movement of ions across the cell membrane

- charge
- conc gradient

15

____ equation is used to determine the value of membrane potential when there is NO NET DIFFUSIOn of any 1 given ion

nernst equation

- will give the electrical potential NRG for 1 ion

16

____ equation is used to determine the RMP when there is NO NET DIFFUSION of ALL ions across the cell membrane

GHK

- gives the reversal potential

17

_____: the ionic flow that will occur once the channel opens

driving force

18

_____= RMP-equil. Potential

driving force

19

the larger the _____ , the faster the ionic current will travel

driving force

20

What are three channel types

leaky ions
ligand
voltage

21

** The _____ gated channel signal the ____ gated channel

ligand signal the voltage gated

22

Changes in membrane potential affect the props of _____

voltage gated

23

when the membrane potential moves ____mV toward positive the voltage gated channel will open

20mV

24

____ gated channels have an all or non mechanism

voltage gated

25

_______: the current flow of voltage gated channels depolarize and further AP regeneration along the neuronal axon , repeats until it reaches the terminal

positive feedback loop

26

Na+ channels use 2 mech to allow ionic flow across the membrane

1. ligand gated channels (AcH)
2. voltage gated channels

27

What is the neurotransmitter that is used to stim the ligand gated channel of Na+

AcH

28

EPSP is due to ___ ions

Na+

29

IPSP is due to ___ ions

Cl-

30

______ ions cause hyperpolarization.
______ions cause depolarization

Cl- = hyperpolar
Na+ = depolar

31

How is a graded potential turned into an AP

summation

- leakage in the membrane prevents EPSP from going straight into an AP

32

The EPSP has to be summed to threshold at ___ to ___ mV above resting potential for a spike to occur= AP

15 to 20mV

33

_____ : where the axon and the stoma meet. Has Na+ channels that can illiciate AP

axon hillock

34

Voltage gated Na+ channels inactivated via _____ mechanism

ball and chain
- keeps the AP moving in one direction

35

___ voltage gated channels only open after the cell has depolarized so much that the membrane is close to +30mV

K+

(overshoots)
- at this pt there is a driving force for K+ to move out so that it can go back to its equil of -90mV (repolarize)

36

K+ equilibrium potential is ____ mV. When this membrane potential is reached the cell is said to be in ____

-90mV = Repolarization

37

Na+/K+ ATPase pump begins working when it senses an increase in intracellular ____ conc

Na+

38

____period: voltage gated Na+ channels woll not open, regardless of stim strength

absolute refractory period

39

_____period: the voltage gated K+ channels have opened, the driving force for K+ to leave the cell is stronger than the driving force for Na+ to enter

relative refractory period

- must have a very high Na+ stim for an AP to be acheiveable

40

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

conductance

41

Conductance is the inverse of _____

resistance

42

Ohm law equation

V= I x R

velocity = current X resistance

43

greater resistance in the membrane than in the cytoplasm, the current will tens to flow through the ____rather than leak back out into the ___

flow through the cytoplasm
instead of back out into membrane

(path of least resistance)

44

the fatter the axon, the ______ it has for ions to flow in

more area

45

______ causes axons to conduct AP faster

myeline

46

______: myelinates axons conduct AP faster than unmyelinates axons

saltatory conduction

47

____ channels are used in vesicle binding and release of neurotransmitter

voltage gated Ca+2

48

voltage gates Ca+2 channels are used in ___ binding and release of ____

vesicle binding and release of NT

49

____ & ___ are docking proteins that tie vesicles to active zones

actin & synaptophysin

50

Ca+2 causes ____ to contract, and bring vesicles forward to the membrane

actin

51

2 actions that occur when there is a Ca+2 influx

1. causes actin to contract - brings vesicles forward
2. activates Calmodulin, causes release of vesicle content into the cleft

52

When Ca+2 binds to ____ , vesicle content is released into the cleft

calmodulin

53

____ helps to withdraw vesicle components back into the synaptic cleft after Ca_2 binds to calmodulin

clathrin

54

A ___ amt of NT is released for ea. AP

fixed