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trisemester 3 TCC > physiology neurophys > Flashcards

physiology neurophys Flashcards

(105 cards)

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1
Q

electrical potential inside a neuron is

A

70 millivolts more negative than the potential in the extracellular fluid on the outside of the fiber

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2
Q

resting membran potential of a neuron is produces by the total

A

ion concentration differences across the membrane

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3
Q

what is the reversal of potential referring to

A

the charges switch on the outside from negative to positive and in the inside from positive to negative

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4
Q

at the end of the AP what happens to the charges?

A

it restores itself

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5
Q

propagates refers to

A

how the AP moves along the neuron like a wave

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6
Q

if a charge is below the threshold stimulus what will happen?

A

an AP is NOT generated due to it being an “all or nothing response”

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7
Q

at rest is there more Na+ outside or inside of the cell at rest?

A

outside

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8
Q

there is high amounts of Na+ inside of the cell?

T/F

A

F

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9
Q

at rest inside of the membrane it is

A

negative

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10
Q

at rest there is highest amounts of this ion inside of the cell?

A

K+

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11
Q

at rest outside of the membrane is

A

positive

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12
Q

at rest the membrane is _______ to Na+

A

impermeable

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13
Q

nerve cells and muscle cells are capable of doing this because they are known as “excitable”

A

self-generating electrical impulses across their membrane

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14
Q

formation of membrane potential involves these 4 things

A
  1. selective permeability
  2. concentration differences of ions
  3. electrical potential
  4. separation of charge
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15
Q

resting membrane potential is established due to the difference

A

of EXCITABLE cells across the membrane at rest

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16
Q

how is a membrane potential created

A

a concentration difference of ions across a semi-permeable membrane

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17
Q

nernst equation is converts what to what?

A

concentration difference for an ion into a voltage

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18
Q

what is expressed at a intracellular potential relative to extracellular potential

A

membrane potential

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19
Q

resting membrane potential is established by

A
  1. diffusion potentials
  2. membrane permeability
  3. electrogenic nature of the Na+K+ pump
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20
Q

potassium ion will diffuse in what direction pertaining to a cell

A

outward

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21
Q

the loss of K+ inside of the cell results in what?

A

a negative charge inside of the cell

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22
Q

what is the driving force of diffusion

A

the equilibrium potential

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23
Q

what is the mv of the potential difference needed to stop further net diffusion of k+ out of a neuron?

A

-90

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24
Q

diffusion of Na+ into the cell will create a

A

positive charge inside of the cell

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25
the potential difference in mv to stop further net diffusion of Na+ is
65+
26
neural membranes are more permeable to this ion?
K+
27
which of the pumps contribute most to the RMP?
potassium leak channels
28
which pump is responsible for maintaining the Na+ & K+ concentraion difference across the cell membrane
Na+K+ ATPase pump
29
what pump helps establish a Negative electrical potential inside cells?
Na+K+ATPase pump
30
E (equilibrium = wants to get here) of Na+ =
+65
31
E K+ =
-90
32
E ca2+ =
+120
33
depolarization
more positive and less negative membrane potential
34
repolarization/hyperpolarization
making the membrane potential more negative/ less positive
35
major ion contributing to depolarization
Na+
36
the major ion contributing to repolarization?
K+
37
gates of gated ion potentials are referred to as
protein/widgets that regulate the channels
38
when a channel is open the ions it is selective to pass by ______ diffusion
passive (no atp)
39
the ion pass through the gates down a (n)
electrochemical gradient
40
which voltage gated channels are responsible for the upstroke phase/depolarization?
voltage gated Na+ channels
41
threshold in mv for excitable membrane?
+ 55
42
why can we not get another AP when in the absolute refractory period
because ALL the Na+ gates are open
43
why can we get somewhat of an AP when in the relative refractory period?
because some of the Na+ gates may have closed & there is a GREATER than usual depolarizing current applied
44
when does the relative refractory period take place
right after the absolute refractory period
45
realtive refractory period overlaps with this?
hyperpolarization
46
voltage K+ channels are responsible for
repolarization
47
voltage gated K+ channels speed versus voltage Na+ channels?
K+ is slower to open
48
restoration
return to RMP
49
repolarization does not restore
resting ionic conditions
50
repolarization retores
resting electrical condition
51
restoration of resting ionic conditions is the function of
Na+ K+ ATP Pumps
52
why does the Na+ K+ ATPase pump require ATP?
it requires a lot energy to maintane the high [Na+] outside of the cell and high [K+] inside of the cell which is AGAINST their [] gradients
53
2 factors the increase the conduction velocity of the AP along a nerve
increase the size and myelination of nerve
54
the large the fiber the lower the
internal resistance
55
flow of ions occurs at what portion of cell?
nodes
56
myelin is white microscopically because?
it contains fat
57
Myelin incrases membrane ______ & decreases membrane ______
1. resistance | 2. capacitance
58
saltatory conduction referrs to ?
the jumping of an axon in myelinated axons
59
length of stimulus and length of depolarization have what kind of relationship?
direct ~ | as length of stimulus increases the length of depolarization increases
60
if excitatory neurotransmitter is stimulated it causes
depolrization of postsynaptic cell - closer to threshold potential
61
if neurotransmitter is inhibitory is causes
hyperpolerization of the postsynaptic cell
62
what makes the postsynaptic neuron more likely to fire past threshold in a graded potential?
EPSP
63
what makes a postsynaptic neuron hyperpolarize in a graded potential
IPSP
64
what lead to the opening of a Na+ channel?
EPSP
65
what can decrease the K+ diffusion outwardly?
EPSP
66
what is responsible for making the inside of the cell more excitatory?
EPSP makes it more positive inside of the cell than normal
67
large amount of this within cell will increase the likelihood that the postsynaptic cell reaches the threshold
EPSPs
68
IPSPs induce
an increase of movement of k+ out of the neuron
69
summation of a graded potential is defined as
addition of post-synaptic potential to reach threshold
70
two ways that presynaptic information may be integrated in a graded potential
spatially and temporally
71
spatially refers to the
firing of different neurons
72
temporally refers to
same neuron fires at a different rate
73
spatial summation is when
2+ presynaptic inputs from different locations arrive at a postsynaptic cell simultaneously
74
do both inputs for a spatial summation need to be excitatory?
yes if not then they will cancel each other out
75
temporal summation occurs when
two presynaptic inputs arrive at the post synaptic cell in RAPID SUCCESSION
76
what is defined as a rapidly repeated stimulation that eventually overlaps in time and causes a summation
temporal summation
77
with graded potential what can vary?
amplitude
78
graded potential can undergo
summation
79
do graded potential have threshold?
no
80
does graded potential have a refractory period?
no
81
in graded potential what happens to distance as the amplitude decreases
it decreases
82
duration may vary due to
intitiating conditions
83
what is the one major event in AP's?
depolarization
84
graded potential has 2 major events
depolarization and hyperpolarization
85
an action potential can be summed? | T/F
FALSE
86
most synapses are
chemical
87
electrical synapses have what kind of junctions?
gap
88
gap junctions allow for
1. very fast conduction | 2. simultaneous activation
89
synaptic clefts is the
gap between the presynaptic cell membrane and the post
90
what is being transmitted across the synaptic cleft?
neurotransmitter
91
neurotransmitter binds to what?
postsynaptic terminal
92
NMJ also known as
cholinergic synapse
93
NMJ synapse between
motor neurona nd a muscle fiber
94
NMJ is Known is an example of a
chemical synapse
95
what is released at the NMJ
ACh
96
choline acetyltransferase is
an enzyme that forms ACh
97
botulins toxin blocks what?
the release of ACh
98
botulins health effects
parlysis of skeletal mm. | death due to respiratory failure
99
curare action
competes with ACh for nicotinic receptors int eh motor end plate decreasing the size of EPP
100
effect of curare
paralysis --> death
101
D-tubocurarine can be used to
relax skeletal mm.
102
Can one graded potential elicit an AP?
No
103
meaning that a graded potential is less than what?
threshold
104
the stimulus of a graded potential may be
chemical ot sensory
105
role of neurotransmitters in a graded potential
can either by excitatory or inhibitory

trisemester 3 TCC (25 decks)

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