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A/P > Lecture 6; 9/6 > Flashcards

Lecture 6; 9/6 Flashcards

Beginning of test 2

1
Q

Define: Polarization

A

A difference in electrical charge on the inside and outside of cell

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2
Q

Are cells polarized at rest?

A

Yes

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3
Q

What is the charge of a resting cell?

A

about negative 80

-80

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4
Q

What happens to the charge of the cell during an AP? What is this called?

A

Becomes more positive

Depolarization: Happens when the cell is turned on
Cell becomes less polar

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5
Q

What happens when a cell is hyperpolarized?

A

Cell becomes more polar

Requires more stimulus to fire an AP
More difficult to excite

When polarity of the cell dips under the resting membrane potential

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6
Q

What is repolarization?

A

Return to normal V(rm) from depolarized state (AP)

Becoming more negative after an AP

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7
Q

More positive means

A

Less negative

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8
Q

Slow Ca++ channels need repolarization of _______ in order to function properly

A

Na+ channels

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9
Q

You can have another AP with repolarizing.

A

No.

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10
Q

What is V-G Ca++ channels called?

A

L-type channels

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11
Q

What can block the L-type channels?

A

DHP (hydropyridine Ca++ channel blockers)

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12
Q

K+ is ____ times more permable than Na+ in a resting cell

A

10

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13
Q

Cl- makes the inside of the cell more ____

A

Negative

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14
Q

In finding EMF, what do we have to know?

A

Relative permeability of each ion that the cell is permeable to

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15
Q

What ion plays an important role in the nervous system?

A

Cl-

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16
Q

What role does Cl- play in the nervous system?

A

Cl- permeability is adjusted to hyperpolarize the cell to suppress electrical activity in excitable cells

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17
Q

What do GABA receptors do?

A

Open Cl- channels in neurons to allow Cl- to flood in to make the cell more negative to supress electrical activity.

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18
Q

How does an AP spread?

A

2 way process: Outward if theres enough room

1 way process: It may only spread in one way if AP is generated at end of cell (depolarization takes longer)

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19
Q

The cell repolarizes in the _____ direction that it depolarizes

A

Same

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20
Q

Explain positive feedback in regards to V-G Na+ channels

A

The AP being generated causes the 1st V-G Na+ channel to open. That 1 change is then amplied causing a bunch of them to open until the cell is repolarized.

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21
Q

Neurons that are specialized in communicating to skeletal muscle

A

Motor neurons

22
Q

Each skeletal muscle fiber has at least ___ motor neurons

A

1

23
Q

What happens when a motor neuron is activated?

A

It produces an AP down the myelinated axon

24
Q

What is released from the end of motor neuron after an AP?

A

Neurotransmitter… Ach…

25
Q

What is the target/receiving cell called?

A

Post synapse

26
Q

What is the sending cell called?

A

Pre synapse

27
Q

Where are neurotransmitters released

A

Neuromuscular junction

28
Q

Where do paralytics work?

A

At the NMJ

29
Q

What does NMJ mean?

A

Neuromuscular Junction

30
Q

What does smoking cigarettes do?

A

Causes excess nicotine can cause release in Ach which can cause tremors/shakiness

31
Q

Besides Na+, what other ion can go into via nAch-R on the skeletal muscle and depolarize it.

A

Ca++

32
Q

T/F: Binding sites on the nAch-R need to be binded one at a time to work.

A

F

33
Q

What is close to the nAch-R?

A

Fast Na+ channels

34
Q

What is a nAch-R?

A

Nicotinic Acetylcholine receptor

Negatively-charged ion pore that when simultaneously bound, open up and allow Na+ to flood into a cell

35
Q

What happens when a nAch-R is simultaneously bound?

A

They open for about 1ms

Na+ floods in (Ca+/K+ out)

Na+ activates fast Na+ channels which is the very beginning of an action potential

36
Q

Where does the motor neuron and skeletal muscle meet?

A

NMJ

37
Q

What type of ion does nAch-R repel?

A

Negatively charged ions

38
Q

What does mAch-R mean?

A

muscarinic Acetylcholine receptor

39
Q

Where are mAch-R located?

A

On the SA and AV node smooth muscle of the heart and the lungs

40
Q

Where is the SA and AV node?

A

On left side

On top of the septum

41
Q

How does electrical current flow through the heart

A

SA node - Atrias - AV node - ventricles

42
Q

What nerve specializes in talking to the heart and comes in contact with the SA and AV nodes?

A

The Vagus nerve

L Vagus talks to SA
R Vagus talks to AV

43
Q

What type of receptor is the mAch-R?

A

GPCR

44
Q

What happens when an Acetylcholine binds to a mAch-R in the heart?

A

It activates the receptor

the Alpha amino acid is released and goes to activate the nearby K+ channel where K+ can flood out the cell causing the cell to become more negative.

45
Q

What is normal heart for this class?

A

70-72 bpm

46
Q

What happens with vagal stimulus?

A

HR decreases.

K+ permeability increase
Pacemaker cells are hyperpolarized

47
Q

What do Antimuscarinic drugs do?

A

Increase HR

drug binds to receptor and blocks it.
K+ stays inside the cell keepig it more positive. Making it easier to fire an AP

* When K leaves out of the cell, it becomes more negative making it more difficult to fire an AP

48
Q

Describe a heart beat

A
  1. Vagus nerve stimulated and releases Ach
  2. Ach binds to the mAch-R
  3. The alpha amino acid opens K+ channels to allow K+ to flood out the cell
  4. Cell is hyperpolarized and ready for next beat

a little hyperpolarized is good/ok for the heart

49
Q

If heart wasn’t being influenced by nervous system, how fast would it beat?

A

110 bpm

50
Q

What is atropine?

A

An Antimuscarinic drug

Increases HR

51
Q

Physical pressure can turn a motor neuron on?

A

Yes

52
Q

Describe how physical pressure can turn on a motor neuron.

A

Pressure sentive Na+ channels widen when flattened and generate an AP but up the motor neuron for processing.

A/P (26 decks)

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