Lecture 6: basic physiology of nerve cells Flashcards

(43 cards)

1
Q

What can affect the presynaptic neuron?

A

Stimuli on the dendrites and cell body (the soma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What area generates the action potential?

A

The axon hillock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What response do dendrites and the cell body (soma) make when affected by stimuli?

A

Graded responses that alter membrane potential (depolarise or hyperpolarise)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

At what point is an action potential generated?

A

If the hillock reaches threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What potential does excitatory neurons produce?

A

Excitatory post-synaptic potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What potential does inhibitory neurons produce?

A

Inhibitory post-synaptic potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What type of response can action potentials have?

A

All or nothing response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the thin, ribbon-like cells that commonly wrap around axons called?

A

Schwann cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the effect of the layers of myelin that make a shwann cell called?

A

Myelination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the gaps between Schwann cells where the axon membrane touches the extracellular fluid called?

A

Nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How fast does an AP travel down a myelinated axon?

A

Approx. 150m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How fast does an AP travel down an unmyelinated axon?

A

0.5 to 10 m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The wider the axon, the ____ the AP

A

Faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of neuron are Aalpha?

A

Motor neurons/proprioceptors, muscle spindles, golgi, tendon, organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of neuron are Abeta?

A

touch, mechanical touch/pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of neuron are Adelta?

A

Pain (fast) temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What type of neuron are C?

A

Pain (slow) temp, itch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens if myelination breaks down?

A

Signals no longer work in concert, results in multiple sclerosis

19
Q

What are the two main types of cell-cell propagation?

A

Electrical synapse, chemical synapse

20
Q

Why do electrical synapses act directly and quickly?

A

Gap junctions allow AP to continue from one cell to the next

21
Q

What is a limitation of electrical synapses?

A

Does not allow much variation in the post-synaptic response

22
Q

What molecules are released into the synaptic cleft in chemical synapses?

A

Neurotransmitters

23
Q

What triggers AP on the postsynaptic neuron after a chemical synapse?

A

Binding of neurotransmitters to the post synaptic membrane (can also rebind to trigger more)

24
Q

What is the first step of voltage-activated Ca2+ channels when an action potential arrives at the synaptic terminal?

A

Depolarisation opens the voltage-activated Ca2+ channels

25
What happens when the Ca2+ channels initially open after depolarisation?
[Ca2+] inside is low, so concentration and electrical gradients cause Ca2+ to flow inwards
26
Why are calcium ions important in neurotransmitter translocation?
Ca2+ dependent phosphorylation of v-SNARE proteins
27
What happens to vesicles associated with the docking region of the plasma membrane?
It is then primed through synaptic t-SNARE proteins followed by Ca2_ stimulated fission of vesicle with plasma membrane
28
Where are small neurotransmitters (such as acetylcholine and noradrenaline) synthesised?
Synaptic bulb, then packaged into vesicles
29
Where are large (protein) neurotransmitters synthesised?
In the cell body, transported inside vesicles down axon to synapse
30
What is adrenaline?
Fight or flight neurotransmitter
31
What is noradrenaline?
Concentration neurotransmitter
32
What is dopamine?
Pleasure neurotransmitter
33
What is serotonin?
Mood neurotransmitter
34
What is GABA?
Calming neurotransmitter
35
Criteria for neurotransmitter discovery: the chemical must be produced within a...
Neuron
36
Criteria for neurotransmitter discovery: the chemical must be found within a...
Neuron
37
Criteria for neurotransmitter discovery: when a neuron is stimulated/deploarised, a neuron must...
Release the chemical
38
Criteria for neurotransmitter discovery: when a chemical is released/applied, it must...
Act on a post-synaptic receptor and cause a biological effect
39
Criteria for neurotransmitter discovery: after a chemical is released, it must be able to be
inactivated, either through reuptake or by enzyme that stops the action
40
What type of channels are invovled in producing excitatory post-synaptic potentials?
Glutamate-gated channels
41
How do glutamate-gated channels generate depolaization of the post-synaptic neuron?
Cause a net influx of Na+
42
What channels are involved in producing inhibitory postsynaptic potentials?
GABA and glycine-gated channels
43
How do GABA and glycine-gated channels hyperpolarise the postsynaptic neuron?
Cause an net influx of Cl-