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A And P 1 > ch 12.4 - > Flashcards

ch 12.4 - Flashcards

1
Q

resting membrane potential

A

membrane potential of an unstimulated resting cell

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2
Q

3 important concepts regarding the membrane potential:

A
  1. The extracellular fluid (ECF) and intracellular fluid (cytosol) differ greatly in ionic composition.
    -ecf has high concentrations of sodium and chloride ions , whereas the cytosol has high concentrations of potassium ions + negatively charged proteins.
  2. cells have selectively permeable membranes
  3. membrane permeability varies by ion
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3
Q

current

A

movement of charges to eliminate a potential difference

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4
Q

resistance

A

measure of how much the membrane restricts ion movement

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5
Q

electrochemical gradient

A

the sum of the chemical and electrical forces acting on that ion across the plasma membrane

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6
Q

chemical gradient

A

passive movement of ions across the plasma membrane driven by their concentration gradient

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7
Q

electrical gradient

A

passive movement of ions due to charge differences

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8
Q

equilibrium potential

A

membrane potential which there is no net movement of a particular ion across the cell membrane

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9
Q

sodium potassium exchange pump

A

powered by atp
moves 3 sodium (Na) ions out of the cell + 2 potassium (K) ions into the cell per atp

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10
Q

gated ion channels

A

open and close in response to stimuli

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11
Q

chemically gated ion channels

A

open when they bind specific chemicals or ligands

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12
Q

voltage gated ion channels

A

open or close in response to changes in the membrane potential

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13
Q

mechanically gated ion channels

A

open or close in response to physical distortion of membrane

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14
Q

graded potentials

A

temporary localized change in the resting membrane potential
- can cause depolarizatio and hyperpolarization

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15
Q

repolarization

A

returning to normal resting membrane potential after depolarization

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16
Q

action potentials

A

large depolarization that once initiated, affects the entire excitable membrane

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17
Q

threshold

A

membrane potential at which an action potential begins

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18
Q

all or none principle

A

an action potential is either triggered or not

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19
Q

steps of action potentials

A
  1. depolarization to threshold
  2. rapid depolarization
  3. repolarization
  4. hyperpolarization
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20
Q

refractory period

A

a period during which the membrane will not respond normally to additional depolarizing stimuli

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21
Q

propagation

A

series of steps that move the action potential along the axon

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22
Q

continuous propagation

A

occurs in unmyelinated axon

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23
Q

saltatory propagation

A

-occurs in myelianted axons

24
Q

3 groups of axons

A

type a fibers
type b fibers
type c fibers

25
Q

synapse

A

a specialized site where the neuron communicates with another cell

26
Q

types of synapses

A

electrical
chemical

27
Q

electrical synapses

A

signal transmitted via direct physical contact between cells

28
Q

chemical synapses

A

signal transmitted across a gap using a chemical signal (neurotransmitter)
- most common type of synapse

29
Q

types of chemical synapses

A

axoaxonic
axosomatic
axodendritic
neuromuscular junction
neuroglandular junction

30
Q

neurotransmitters

A

chemical messengers contained within synaptic vesicles in the axon terminal of the presynaptic cell

31
Q

neurotransmitter function

A

alters the membrane potential of the other neuron

32
Q

cholinergic synapses

A

releases acetylcholine

33
Q

synaptic delay

A

a delay between the arrival of the action postsynaptic membrane

34
Q

synaptic fatigue

A

response of the synapse weakens due to insufficient neurotransmitter until the neurotransmitter has been replenished

35
Q

types of neurotransmitters

A

excitatory: caused depolarization of postsynaptic membrane + promote generation of action potentials

inhibitory: causes hyperpolarization of the postsynaptic membranes and suppresses generation of action potentials

36
Q

biogenic amines

A

-norepinephrine (excitatory)
-dopamine ( inhibitory or excitatory effects)
- serotonin

37
Q

amino acids

A

glutamate
glycine
gamma-aminobutyric acid (GABA)

38
Q

neuropeptides

A

small peptide chains synthesized and released by the axon terminal

39
Q

neuromodulator

A

compound released by a neuron that alters the other neuron’s response to specific neurotransmitters

40
Q

opioids

A

relieve pain and bind to the same receptors as opium and morphine

41
Q

classes of opioids in CNS

A

enkephalins
endorphins
dynorphins

42
Q

disolved gases

A

nitric oxide
carbon monoxide

43
Q

ionotropic effect

A

a direct effect on the membrane potential by opening and closing chemically gated ion channels

44
Q

postsynaptic potential

A

graded potentials that develop in the postsynaptic membrane in response to a neurotransmitter

45
Q

excitatory postsynaptic potential

A

graded depolarization of postsynaptic membrane

46
Q

inhibitory postsynaptic potential

A

graded hyperpolarization of postsynaptic membrane

47
Q

summation

A

integrates the effect of all incoming graded potentials

48
Q

temporal summatio

A

summation of rapid, repeated stimuli at a single synapse

49
Q

spatial summation

A

summation of simultaneous stimuli that arrive at multiple synapses

50
Q

facilitation

A

bringing the membrane potential of the initial segment closer to threshold

51
Q

presynaptic inhibition

A

decrease in the rate of neurotransmitter release at the presynaptic membrane

52
Q

presynaptic facilitation

A

increase in the rate of neurotransmitter release at the presynaptic membrane

53
Q

depolarization is also known as

A

rising phase

54
Q

repolarization is also known as

A

falling phase

55
Q
A

A And P 1 (41 decks)

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