BASIC NEUROPHYSIOLOGY Flashcards Preview

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Flashcards in BASIC NEUROPHYSIOLOGY Deck (43)
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1
Q

how do neurons transmit signal

A

via chemical or electrical transmission

2
Q

how are neurons classified

A

based on morphology

3
Q

Where do synapses (and communication) occur

A

dendritic spines

4
Q

What is the most dynamic part of the dendrite

A

the spines - grow and prune

5
Q

A chain of neurons is reffered to as a ____

A

pathway

6
Q

A bundle of axons is referred to as a ___

A

tract

7
Q

What do polydendrocytes do

A

generate new oligodendrocytes or other new cells in nervous system

8
Q

What do astrocytes do

A
  • Support cells
  • Ioin hemeostasis
  • transmitter uptake
  • Modulation of synaptic activity
  • Blood brain barrier
9
Q

What are the differences between oligodendrocytes and schwann cells

A
Oligodendrocytes 
- CNS 
- Can myelinate multiple axons 
Schwann Cell 
- PNS 
- Can ensheath only one axon
10
Q

Where is K+ low? high?

A

Outside of cell

Inside of cell

11
Q

Where is Na+ low? High?

A

In cell

Outside of cell

12
Q

How does the NA+/K+ pump work

A

ATPase moves 3 Na+ out of cell and 2 K+ into cell

13
Q

When is equilibrium potential or electrochemical equilibrium achieve

A

When there is a balance between the concentration gradient and the electrical gradient

14
Q

What does the Nernst equation describe

A

The equilibrium potential of 1 ion

15
Q

What does the Goldmann equation describe

A

the equilibrium potential of multiple ions and their respective gradients

16
Q

What occurs during depolarization of cell

A

Na+ influx inward current following chemical gradient

17
Q

What occurs at peak of action potential

A

Na+ can not flow in because it is repelled by electrical gradient
Na+ channels close
K+ channels open and K+ leaves cell

18
Q

When does the Na+/K+ pump kick in

A

In hyperpolarization

19
Q

What is active current

A

The movement of ions through ion channels

i.e. action potential

20
Q

What is passive current

A

The shuttling of charge along a neuronal process

21
Q

What decreases capitance

A

decreasing axon diameter or by preventing the accumulation of charge

22
Q

What decreases resistance

A

Increasing diameter of axon

23
Q

The velocity of an AP is determined by…

A

both active and passive current

24
Q

What is resistance? what is it measured in

A

Difficulty of moving ions, measured in Ohm

25
Q

What is capicitance

A

How much charge the membrane can hold

26
Q

Where are Na+ channels located

A

At the nodes of ranvier

27
Q

Do you have a membrane acting as a capacitor at the nodes of ranvier

A

yes but the area is so small it is not a problem

28
Q

What occurs at the nodes of ranvier

A

You are regenerating the action potential. Costs you ATP

29
Q

What occurs if you lose your myelin

A
  • The next set of NA channels is way too far away and you cant transport the AP
  • you can insert additional Na+ channels but then you are using more ATP and the signal is travelling slower
30
Q

What does the distance between nodes depend on

A

The axon diameter (which influences resistance) and the thickness of the myelin sheath (which prevents leak current)

31
Q

How do you decrease capacitance

A

myelination

32
Q

how do you decrease resistance

A

increase axon diameter

33
Q

Electrical synapses are coupled by____

A

gap junctions

34
Q

What are the steps to an electrochemical synapse

A
  1. action potential
  2. voltage gated Ca2+ channels open
  3. Ca2+ influx causes neurotransmitter-filled vesicles to fuse with the cell membrane
  4. Neurotransmitter is released into the synaptic cleft and binds to receptors, this causes the opening of ion channels
  5. Post-synaptic cells depolarizes and an action potential is generated
35
Q

What occurs once a glutamate receptor is activated

A

allow positive ions to enter cell causing an excitatory post synaptic potential

36
Q

Neurotransmitter receptors can be couples to ____ or _____

A

ion channels or intracellular signalling cascades

37
Q

What are Neurotransmitter receptors that are coupled to ion channels called

A

ionotropic receptors

38
Q

What are Neurotransmitter receptors that are coupled to intracellular signalling cascades called

A

metabotropic receptors

39
Q

What are the differences between C-fibres and delta fibres

A

C-fibre - small diameter, unmyelinated, dull pain

Delta fibres - medium diameter and myelinated. Sharp pain

40
Q

What are the characteristics of motor nerves

A

fast and super responsive therefore large diameter and myelinated

41
Q

How do stretch receptors in the body work

A

they generate a depolarization that is proportional to the amount of stretch - Generator potential

42
Q

What occurs when the generator potential is large enough

A

an action potential is produced

43
Q

Sensory receptors change one form of energy into…

A

electrical signalling - The receptor potential