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Cardio > Electrophysiology > Flashcards

Electrophysiology Flashcards

1
Q

RMP

A

Resting Membrane Potential

-90 mV for a motor neuron

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2
Q

Which region is negatively charged RELATIVE to the other?

A

Intracellular surface relative to extracellular surface

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3
Q

Resting motor neuron has a high [intracellular] of ____ and [extracellular] of _______

A

K+

Na+

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4
Q

Na/K ATPase is essential for maintaining

A

Resting electrochemical gradients for electrogenic cells

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5
Q

EMF

A

Electromotive Force

Tendency for ion to move in one direction or another

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6
Q

EMG is dependent on (2)

A

Na, K, Cl concentrations

Membrane permeability of the ions

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7
Q

RMP is set by

A

K concentration gradient across cell membrane

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8
Q

What happens if plasma K is elevated?

A

Concentration gradient is lowered across cell membrane
RMP is less negative
Membrane depolarizes (less K is leaving)

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9
Q

Larger the K concentration gradient =

A

Greater negativity in cell

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10
Q

AP can be recorded and measured as

A

Electric current (INa+)

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11
Q

If voltage-dependent gates are open then….

A

There’s a significant change in net ionic flux

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12
Q

3 general phases of AP

A
  1. Resting
  2. Depolarization
  3. Repolarization
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13
Q

Resting phase

A

Polarized

In RMP

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14
Q

Depolarization

A

Inc. permeability to Na due to opening of voltage-gated channels
Membrane becomes less negative

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15
Q

Threshold potential

A

Membrane voltage where INa+ isn’t opposed by any other forces

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16
Q

Towards end of depolarization, what happens?

A

Voltage gated K being to open to diffuse out of the cell

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17
Q

Repolarization

A

Voltage gated Na close

Voltage gated K stay open since membrane is still permeable

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18
Q

2 types of voltage gated Na channels

A

Activation (extracellular side)

Inactivation (cytoplasmic side)

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19
Q

Resting conformation for voltage gated Na channel

A

Inactivation gates open

Activation gates closed

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20
Q

Depolarization conformation for voltage gated Na channels

A

Inactivation and activation gates open

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21
Q

Repolarization conformation for voltage gated Na channels

A

Inactivation and activation gates closed

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22
Q

Voltage gated Na and K channels are ________ dependent for _______

A

Voltage and time

Activation and inactivation

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23
Q

Greatest % of K channels open around

A

60mV

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24
Q

Voltage gated Ca channels are _________ activating

A

Slow

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25
Q

2 types of Ca channels

A

L- type (long)

T- type (transient)

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26
Q

T-type channels

A

Pacemaker of SA node

Activate and inactivate over more negative Vm

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27
Q

L-type channels

A

Plateau phase of AP in vascular SM and cardiac myocytes

High threshold for activation

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28
Q

Threshold potential can be changed in response to

A

Physiological conditions

Ex: temperature, hypoxia, pH, anesthesia

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29
Q

Subthreshold stimuli activate _____ to allow _____ influx

A

Ligand gated Na channels

Na

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30
Q

Graded potentials are proportional in ______ to the ______

A

Amplitude

Stimulus strength

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31
Q

Graded potentials are also known as ______

A

Subthreshold changes in membrane potential

32
Q

2 types of graded potentials

A

Excitatory post-synaptic potentials (EPSP)

Inhibitory post-synaptic potentials (IPSP)

33
Q

To reach threshold, some graded potentials can ______ which is common in regulating communication between ______ and ______

A

Summate
Neurons (neuroneruonal transmission)
Motor neurons and skeletal muscle (neuromuscular)

34
Q

Absolute Refractory Period

A

Also known as effective refractory period

Another AP can’t be initiated while Na inactivation gates are closed

35
Q

Absolute refractory periods extends until

A

Enough voltage gated na channels are in resting conformation

36
Q

Relative Refractory Period

A

Limited APs can be generated during the recovery phase which a strong enough stimulus

37
Q

proper Na and K concentration needed for RMP is restored by

A

Na/K ATPase

38
Q

How many APs can be fired before the [Na] and [K] prevents generating another AP

A

100,000 - 150,000

39
Q

Common stimuli of APs are (6)

A 
Ions
Neurotransmitters
Mechanical manipulation of neural tissue
Electric current
Electromagnetic energy
Pharmacological agents
40
Q

AP spread electrical activity to ______ of the plasma membrane due to migration of _____ between the ______ area and __________ regions of resting plasma membrane

A

Adjacent portions
Na+
Depolarizes area
Adjacent

41
Q

Migration of Na induces: (3)

A
  1. Membrane depolarization of adjacent regions
  2. Activation of voltage gated Na channels
  3. AP
42
Q

An AP is propagated from the _______, along the ______ via a series of _________

A

Initial activation site
Membrane
Na induced depolarizations

43
Q

Myelin (2)

A

Phospholipid/cholesterol substance

Formed by Schwann cells

44
Q

Myelin sheath

A

Prevents conductivity

45
Q

AP are NOT generated where?

A

Within myelin

46
Q

AP can only be generates in the

A

Nodes of Ranvier

47
Q

Saltatory conduction requires less ______ than the _____

A

Energy

Cable-like conduction of AP in non-myelinated neurons

48
Q

Repolarization always relies on

A

K (Potassium!)

49
Q

SA node maintains

A

Cardiac rate and rhythm

50
Q

HCN channels stand for

A

Hyperpolarized-activated Cyclic Nucleotide-Gated

51
Q

During the depolarization phase in pacemaker potentials, ________ subsequently inactivate

A

T-type Ca channels

52
Q

Hyperpolarization of Pacemaker potential is needed in order to

A

Reactivate HCN channels to allow the process to repeat

53
Q

Plateau potentials regulate

A

Cardiomyocyte contractility

54
Q

Inward positive current results in

A

Depolarization

55
Q

Outward positive current OR inward negative current results in

A

Repolarization or hyperpolarization

56
Q

Plateau potential steps (4)

A
  1. Na influx (depolarization)
  2. Transient K dependent repolarization
  3. Activate voltage gated Ca channels (moves in), outward K flow
  4. Diff. Isoform of K channel activated (repolarization)
57
Q

Nociceptors

A

Mediate pain signal

Somatic sensory receptors

58
Q

Nociceptor afferents are ______ and consist of ______ and _______ fibers

A

Nerve fibers relaying into CNS
Myelinated
Unmyelinated

59
Q

Myelinated fibers are (3):

A

Medium to large diameter
Fast conducting
Relay fast pain (sharp, intense)

60
Q

Type C pain afferents (4):

A

Small diameter
Unmyelinated
Slow conducting
Relay sensations of dull, burning pain

61
Q

Local anesthetics work by

A

Reversible blocking AP

62
Q

Local anesthetics are usually _____ at pH ____ and are _____

A

Weak bases
7.4
Lipid soluble

63
Q

How does an anesthetic work? (4)

A
  1. Protonation due to acidic intracellular pH of neuron
  2. Bind to receptor site of voltage gated Na channel
  3. Prevents activation gate from opening
  4. Neuron can’t depolarize and fire AP so pain signal isn’t relayed
64
Q

2 ways a synaptic transmission (AP) is relayed

A
  1. Neuroneuronal (between neurons)

2. Neuromuscular (between neurons and affector tissues)

65
Q

Synaptic Transmission steps: (6)

A
  1. Voltage gated Ca channels open
  2. Can flows into nerve terminus
  3. Ca dependent signaling
  4. Synaptic vessicles fuse to pre-synaptic membrane (on intracellular side)
  5. Neurotransmitters released into synapse
  6. Ligand binds receptor to elicit response
66
Q

Chemical synapses are ____and use _____ to relay _____

A

Wider
Neurotransmitters as messengers
AP between cells

67
Q

Excitatory neurotransmitters

A

Glutamate

Aspartate

68
Q

Inhibitory neurotransmitters

A

GABA

Glycine

69
Q

Electrical synapses are not _____, whereas chemical synapses make up the _______

A

Common

Majority

70
Q

Chemical synaptic transmitting categorized into: (2)

A

Ionotropic

Metabotropic

71
Q

Ionotropic transmission

A

Uses NT to activate ligand gated channels in post-synaptic membrane
Ligand channels can be excitatory or inhibitory

72
Q

Which type of chemical transmission is faster? (Ionotropic or Metabotropic)

A

Ionotropic transmission

73
Q

Metabotropic transmission

A

Relies on release of NT and the activation of receptor-mediated signaling in effector tissue

74
Q

Example of metabotropic transmission

A

Controlling heart rate via ACh activating CM2 receptors in SA node

75
Q

Example of ionotropic transmission

A

Nicotine-cholinergic receptor in skeletal muscle (excitatory)

76
Q

Synaptic fatigue occurs

A

After sustained stimulation of neuronal transmission

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