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Flashcards in Action Potentials Deck (50)
1

Why are AP's imp for dentists

for local anaesthesia and pain etc

2

what are the diffenret chemical singling of the body

short distance - synapse
long distance - hormones

3

how fast is the chemical singling in the body

relatively slow

4

what are the types of electrical signalling in the body

graded potentials
AP's

5

what are graded potentials

short distance
vary
fizzle out at nerve endings

6

what are AP's

long distance
all or none
fast 120m/s

7

is the nerve membrane a good insulator

no poor as phospholipids are leaky and in aq enviro

8

is the cytoplasm good conductor

no poor

9

what happens to signals in nerves over 2-3mm and what is this due to

decays
due to high resistance and poor insulation

10

what is used in nerves to help with propagations of signals

AP's

11

what is a resting mem pot

Separation of opposite charges across a membrane

12

what causes a rest mem pot

perm of key ions
corn grad for key ions
gradients maintained by active transporters

13

do all cells have rest me pot

yes

14

what are excitable cells

nerve and muscle

15

what are the extra/intracellular conc and relative perm of Na, K an anion

Na
extra - 150
intra - 15
RP - 1

K
extra - 5
intra - 150
RP - 25-30

anion
extra - 0
intra - 65
RP - 0

16

roughly explain the Na/K pump

uses ATP
transports 3 Na out
2 K in
helps maintain conc grads

17

si the mem perm or imperm to K

perm at rest

18

what is the electrochem gradient for K

chemical - k out
electrical - protein anions cant flow out so k attracted in

19

what is the nernst value for K equilibrium potential

-90mV

20

what si the mem at rest like toward Na

much less perm to Na

21

what si the nernst eon value for Na

+60mV

22

how si the resting mem potential formed

due to effects of K and Na
ion with > perm drives mem potential

23

at rest what is the RMP closer to

K equilibrium potential

24

what is the RMP based on

based upon all ions in goldman eqn

25

what is the importance of -50mV

threshold for AP all or none

26

what is depolarisation

going upward more positive cause potential to go up sodium channels open

27

what happens after depolarisation overshoot

K channels delay open and Na channels inactivate rapid depolarisation
K out

28

what is hyperpolarsation

below threshold K channels close and N channels reset

29

what is the hodgkins cycle

threshold depo
Na channels open
increase na perm
Na moves into cell
Depo
N channel open

30

how do 'caine' anaesthetics affect he hodgkins cycle

hold Na channels reversibly closed

31

what is AP propagation

local current flow to adjacent area
raise pot to threshold
voltage gated N channel open
poitve feedback
porpaget along axon

32

what si a refractory period

time when cannot reactivate a Na channel

33

what are th two types of refractory period

absolute and relative

34

what is an absolute refractory period

Na channels not in rest configuration
an AP can't occur

35

what is a relative refractory period

K gates open
mem is hyper polarised
an AP can occur need larger stimulus

36

what does a refractory period do in terms of directions

means that nerve signals cannot backfire only propagated in one direction

37

what does the width of an axon do to conduction velocity

increase axon diameter
lower resistance
faster conduction

38

what does myelination do to conduction velocity

insulates
node ranvier jumps
local current flow node to node
depo jumps

39

what re the types of nerve fibres

C
A delta
A beta
A alpha

40

what does a C nerve do

slow burning pain
high resistance coz thin and non myelin
smallest nerve slow velocity

41

what is a A delt nerve

faster sharp pain
myelin sheath so faster condition and is wider

42

what is a A beta nerve

wider and myelinated
sensory ones, mechanoreceps

43

what is a A alpha

biggest nerve
motor to muscles
widest and myelinated

44

why rent all nerve A alpha

to big to fit in body need small to fit in places or would be huge

45

what re incoming nerves

afferent from periphery to centre

46

what are outgoing nerves

efferent from center to periphery

47

what are the fastest nerves linked to

proprioception - knowing about self form and what body doing

48

what is good to keep in mind about nerve size with dentistry

affects diff with LA

49

what are the easiest yes of nerves to block

smallest most difficult widest

50

what are he first type of nerves to be blocked

pain then touch