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A/P > Lecture 7; 9/11 > Flashcards

Lecture 7; 9/11 Flashcards

Test 2

1
Q

What is sub-threshold?

A

Below the threshold required to have an AP

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2
Q

What is acute sub threshold potentials?

A

Weak stimulus/depolarization

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3
Q

Define: Threshold

A

Bar the stimulus/depolarization has to get over to have AP

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4
Q

The higher the stimulus over the threshold =

A

The faster the AP (also means stronger stimulus)

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5
Q

T/F: Every cell’s threshold potential is about -65

A

F

Every cell’s threshold for an AP is different depending on the type of tissue

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6
Q

What happens if the stimulus barely crosses the threshold?

A

Delayed AP

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7
Q

What is L-Type?

A

V-G Ca++ channels

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8
Q

What do L-type channels do in the heart?

A

They open slowly after depolarization which results in the plateau

Ca++ floods into the heart causing depolarization and contraction of the myocardial.

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9
Q

What does the depolarization plateau tell you?

A

How well the heart is going to pump

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10
Q

How long should the depolarization plateau be?

A

About 0.5 seconds

Compared to the usual 1ms

This gives the heart muscle time to contract and pump blood

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11
Q

If we decrease Cl- in the nervous system what could happen?

A

Seizures

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12
Q

We want to keep the nervous system_____

A

hyperpolarized

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13
Q

IV Ca++ and Mg++ _______ neuronal and muscular cell electrical excitability

A

Decreases

“Calming effect”

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14
Q

Describe a Calcium

A

Double charged
Large and clunky
Huge concentration gradient
Hangs out by cell wall

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15
Q

What happens to Na+ and K+ when you give Ca++?

A

Ca++ will block the leaky Na+ channels because Ca++ wants to get into the cell real bad, but its too big to go through there.

ECF Na++ will increase

ECF K++ will decrease and ICF will increase

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16
Q

What does decreased levels of Ca++ in the blood do?

A

More Na++ going into the cell which will increase the V(rm) = more excitable cell

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17
Q

T/F: Calcium inhibits electrical activity of the cell

A

T

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18
Q

What happens if you increase your serum K+?

A

You decrease the concentration gradient
K+ will not leave as fast

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19
Q

Where are 2 places that AP happen?

A

Motor neuron
Skeletal muscle

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20
Q

Trousseau sign is caused by

A

Hypocalcemia

Spasms in wrist

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21
Q

Chvostek’s sign is caused by

A

Hypocalcemia

Spasms in face

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22
Q

What does tetany mean?

A

involuntary muscle spasms

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23
Q

You can give a _____ bolus for tissues that are too depolarized

A

Ca++/Mg++

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24
Q

T/F: V-G Na++ channels are clogged by Ca++

A

F

Only effects leaky channels

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25
Q

Myelin Sheath is a ______ structure that helps send AP ________

A

Robust

Quickly

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26
Q

How does the diameter of the nerve effect the rate of the AP?

A

Wider = Faster

More narrow = more resistance = slower

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27
Q

What are the 3 things that affect the rate of an AP?

A

Length of nerve
Diameter of nerve
Presence of Myelin sheath

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28
Q

How does myelin effect rate of AP?

A

No myelin = slow

More myelin = faster

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29
Q

How is myelin formed?

A

Schwann cell nucleus grows overtime and wraps around the neuron in a spiral

As it spirals, the water is squeezed out and it becomes a good insulator.

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30
Q

What does a myelin sheath do?

A

-Prevents Na+ from being pumped back out during an AP by a Na/K pump

-Allows faster conduction of AP

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31
Q

What is the Nodes of Ranvier?

A

High density area packed with Lots of fast Na+ channels, Na/K pump, and K+ channels

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32
Q

What is Saltatory conduction?

A

Jumping from 1 node of renvier to another to spread the AP

33
Q

What is part of the CNS?

A

Brain, spinal cord, Cranial nerve 2 (optic nerve)

34
Q

T/F: Myelin makes cells less prone to ischemia

A

T

35
Q

T/F: Myelin adds protection from crush injuries

A

T

36
Q

What cell is responsible at producing/maintaining myelin in the CNS?

A

Oligodendrocytes

37
Q

What cell is responsible at producing/maintaining myelin in the PNS?

A

Schwann Cells

38
Q

Oligodendrocytes are _____ at reproducing myelin

A

Bad

39
Q

Oligodendrocytes and Schwann cells are ______ cells

A

Glial

40
Q

At what age do you begin to lose myelin?

A

40

41
Q

Myelinated neurons are _____

A

energy efficient

42
Q

Myelinated cell require _____ anesthesia

A

More

d/t fast Na+ channels density at the nodes of renvier

43
Q

If myelin sheath is degraded, what will come back?

A

Na/K pumps

44
Q

What happens to the stuff under the myelin sheath?

A

degraded

45
Q

What diseases are associated with loss of myelin sheath?

A

MS, Optic Neuritis, Guillain-Barre

46
Q

After covid, what disease did we see an increase in regarding loss of myelin sheath?

A

Gullian- Barre

From covid infection, body generated antibodies that affected the nervous system

47
Q

Explain whats going on in demyelinating diseases

A

Since the meylin is degraded or gone Na/K ATP pumps will regenerate

This will make it almost impossible to generate an AP in that area but the Na+ will just get pumped right back out and we will not be able to excite the cell.

48
Q

How does an electrical synapse gap junction work?

A

Simple diffusion ion channel

49
Q

How many connexins make a connexon?

A

6

50
Q

Explain cell signaling with electrical synapse gap junctions

A

fast way to get AP from 1 cell to another

  1. 6 connexins from a connexon
  2. 2 connexions connect to form an ion channel (conduits) that allows the passage of small ions
  3. Gap junction is the area where the connexons meet

Ca++ can go through but its big and it doesnt go well

51
Q

What area has a decrease in Gap junctions to allow for delays?

A

Pacing area of the heart

52
Q

Where are connexions located?

A

In the cell wall

53
Q

Which is faster, a chemical or electrical synapse?

A

Electrical

54
Q

Fiber classification A:

A

Heavily myelinated
AP sent fastest

55
Q

Fiber classification C:

A

No myelination

56
Q

Fiber classification B:

A

Lightly myelinated

57
Q

If information is need to be sent quickly, what class of fibers would it be sent on?

A

Class A

58
Q

What class of fibers are motor neurons under?

A

Class A

59
Q

What is another name for a cell body?

A

Soma

60
Q

Describe a neuron structure

A

-Cell body
-Dendrites
-Axon
- Axon Hillock

61
Q

What is the cell body?

A

Mostly the decision maker

Has lots of mitochondria

charge -60

62
Q

What are dendrites?

A

Receiving end

Recieves info from descending pathways from brain or sensory info from dorsal horn

talks to other neurons

This end is stuck to the anterior horn on the grey matter of the spine

Negatively charged

63
Q

What is the Axon Hillock?

A

Has multiple inhibitory connections (GABA receptors which increase Cl permeability)

Supresses overactivity of the CNS

Most negatively charged

64
Q

What is the Axon?

A

Area that AP is sent down

Used for signaling

Myelinated

65
Q

Excitatory connections will make the dendrite area more _____

A

positive

66
Q

Inhibitory connections will make the dendrite more_____

A

negative

67
Q

Alcohol is a ______ antagonist. It can cause ________

A

GABA

Seizures

68
Q

What happens if you remove the inhibitory connections on the axon hillock?

A

Increase excitability in the nervous system —> seizures

69
Q

What are Glial cells? what are the 4 kind?

A

Supporting cells that can divid and replicate

Astrocytes, Ependymal cells, oligodendrocytes, and microglia

70
Q

What are Astrocytes?

A

Important in BBB

helps maintain balance in CSF, electrolytes, and pH buffer

connects with endothelial

71
Q

What is ependymal cells?

A

Produces and moves CSF with cilia

72
Q

What is Microglia?

A

Acts as immune system

degrades dead cells and keeps the area around the CNS clean

73
Q

What are Oligodendrocytes

A

Form myelin sheath in the CNS
Schwann cells in PNS

74
Q

What are the 3 different types of neurons?

A

Multipolar
Bipolar
Pseudounipolar

75
Q

Describe Neuron: Multipolar

A

Decision making

Cell body attached to dendrites

Cell body at top

Cell body sits on top of axon

AP travels down axon

76
Q

Describe Neuron: Bipolar

A

Special sensory

Ex) Optic nerve

Dendrites at the top

Cell body in the middle

myelinated axon between dendrites and cell body and cell body and bottom

77
Q

Describe Neuron: Pseudouipolar

A

Sensory

Cell body only there to support the structure

Majority of sensory cells outside spinal cord

Decisions made by sensors itself

Feeds in through the posterior/dorsal horn in the grey matter of the spinal cord

78
Q

What type of neuron is a motor neuron?

A

Multipolar

79
Q
A

A/P (13 decks)

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