BASIC NEUROPHYSIOLOGY

Question 1

how do neurons transmit signal

Answer 1

via chemical or electrical transmission

Question 2

how are neurons classified

Answer 2

based on morphology

Question 3

Where do synapses (and communication) occur

Answer 3

dendritic spines

Question 4

What is the most dynamic part of the dendrite

Answer 4

the spines - grow and prune

Question 5

A chain of neurons is reffered to as a ____

Answer 5

pathway

Question 6

A bundle of axons is referred to as a ___

Answer 6

tract

Question 7

What do polydendrocytes do

Answer 7

generate new oligodendrocytes or other new cells in nervous system

Question 8

What do astrocytes do

Answer 8

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

Question 9

What are the differences between oligodendrocytes and schwann cells

Answer 9

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

Question 10

Where is K+ low? high?

Answer 10

Outside of cell

Inside of cell

Question 11

Where is Na+ low? High?

Answer 11

In cell

Outside of cell

Question 12

How does the NA+/K+ pump work

Answer 12

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

Question 13

When is equilibrium potential or electrochemical equilibrium achieve

Answer 13

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

Question 14

What does the Nernst equation describe

Answer 14

The equilibrium potential of 1 ion

Question 15

What does the Goldmann equation describe

Answer 15

the equilibrium potential of multiple ions and their respective gradients

Question 16

What occurs during depolarization of cell

Answer 16

Na+ influx inward current following chemical gradient

Question 17

What occurs at peak of action potential

Answer 17

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

Question 18

When does the Na+/K+ pump kick in

Answer 18

In hyperpolarization

Question 19

What is active current

Answer 19

The movement of ions through ion channels

i.e. action potential

Question 20

What is passive current

Answer 20

The shuttling of charge along a neuronal process

Question 21

What decreases capitance

Answer 21

decreasing axon diameter or by preventing the accumulation of charge

Question 22

What decreases resistance

Answer 22

Increasing diameter of axon

Question 23

The velocity of an AP is determined by…

Answer 23

both active and passive current

Question 24

What is resistance? what is it measured in

Answer 24

Difficulty of moving ions, measured in Ohm

Question 25

What is capicitance

Answer 25

How much charge the membrane can hold

Question 26

Where are Na+ channels located

Answer 26

At the nodes of ranvier

Question 27

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

Answer 27

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

Question 28

What occurs at the nodes of ranvier

Answer 28

You are regenerating the action potential. Costs you ATP

Question 29

What occurs if you lose your myelin

Answer 29

- 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

Question 30

What does the distance between nodes depend on

Answer 30

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

Question 31

How do you decrease capacitance

Answer 31

myelination

Question 32

how do you decrease resistance

Answer 32

increase axon diameter

Question 33

Electrical synapses are coupled by____

Answer 33

gap junctions

Question 34

What are the steps to an electrochemical synapse

Answer 34

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

Question 35

What occurs once a glutamate receptor is activated

Answer 35

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

Question 36

Neurotransmitter receptors can be couples to ____ or _____

Answer 36

ion channels or intracellular signalling cascades

Question 37

What are Neurotransmitter receptors that are coupled to ion channels called

Answer 37

ionotropic receptors

Question 38

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

Answer 38

metabotropic receptors

Question 39

What are the differences between C-fibres and delta fibres

Answer 39

C-fibre - small diameter, unmyelinated, dull pain | Delta fibres - medium diameter and myelinated. Sharp pain

Question 40

What are the characteristics of motor nerves

Answer 40

fast and super responsive therefore large diameter and myelinated

Question 41

How do stretch receptors in the body work

Answer 41

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

Question 42

What occurs when the generator potential is large enough

Answer 42

an action potential is produced

Question 43

Sensory receptors change one form of energy into...

Answer 43

electrical signalling - The receptor potential