Peripheral Nervous System Flashcards

1
Q

What are signals for the PNS?

A

Hormones
Nerves
Muscles

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

What do action potentials require?

A

Excitable cells and voltage gated ion channels

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

What do voltage gated ion channels give rise to? Are they graded or all or nothing?

A

Positive feedback loop

All or nothing

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

The strength of an impulse is altered by what?

A

Number and frequency of action potentials

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

Most voltage gated ion channels use which ion?

A

Sodium

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

When are voltage gated ion channels calcium gated?Are they faster or slower than sodium?

A

Some smooth muscle
Cardiac cells
Endocrine cells
much slower

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

Calcium is a second messenger. What does this mean?

A

It can link with an action potential with intracellular signalling

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

What is the absolute refractory period? What is the state of the ion channels?

A

Interval where a secondary action potential cannot be initiated, no matter the stimulation size
All channels inactivated

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

How many gates are involved in sodium gated ion channels? How many states?

A

2 gates, therefore 3 states

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

What are the 3 stages of sodium based action potentials?

A

Deactivated - low membrane potential, closed
Activated - open
Inactivated - closed for refractory period

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

What is the relative refractory period?

A

Second action potential is inhibited but not impossible
Some sodium ion channels inactivated,
Increased K+ conductance

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

What is a nerve fibre?

A

Part of a neuron

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

What is the cell body of a neutron?

A

Perikaryon

Soma

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

What are dendrites?

A

Receiving antenna of a neuron

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

What are microfilaments and microtubules?

A

Protein networks which provide transport and structure for neurons

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

What are nodes of Ranvier/

A

Gaps in the myelination of an axon

17
Q

What are terminal buttons?

A

Part of presynaptic neurone

Release neurotransmitters into the cleft

18
Q

What is the opposite of saltatory conduction?

A

Continuous conduction

Non myelinated sheath, depolarisation of adjacent parts of the membrane

19
Q

Do synapses give graded or all or nothing excitation? Why are they better than the few ions which transport via gap junctions?

A

Graded

Synchronised and allow communication

20
Q

Are synapses excitatory or inhibitory?

A

Both
If excitatory - depolarise membrane more positive, bring to threshold
Inhibitory - hyperpolarises membrane to make it more difficult to reach the threshold

21
Q

What is EPSP and IPSP

A

Excitatory post synaptic potentials

Inhibitory post synaptic potentials

22
Q

What are the 3 ways neurotransmitter can be removed from the synaptic cleft?

A

Enzyme degradation
Diffusion
Uptake by cells

23
Q

Are neurotransmitters excitatory or inhibitory? What can they be blocked by?

A

Both

Agonists, antagonists

24
Q

What is temporal summation?

A

One presynaptic neurone to one postsynaptic neurone

25
Q

What is spatial summation?

A

Multiple presynaptic neurones to one postsynaptic neurone

26
Q

What is the neuromuscular junction between? Is it excitatory or inhibitory?

A

Motor neurone and skeletal muscle

Excitatory - inhibition by CNS

27
Q

What is the process that takes place in a neuromuscular junction?

A

Action potential in motor neurone propagated to terminal button, which triggers the opening of calcium channels
Calcium enters terminal button and triggers exocytosis of acetylcholine
Acetylcholine is degraded by acetylcholinesterase to acetate and choline
Choline taken back into presynaptic terminal

28
Q

What are the similarities between NMJ and a synapse?

A

Both excitable and separated by cleft
Axon terminals store chemical messenger
Binding of a neurotransmitter leads to ion channels opening and change in membrane potential
Changes in membrane potential are graded

29
Q

What are the differences between NMJ and a synapse?

A

Between two neurones, between motor neurone and skeletal muscle
1 to 1 transmission of action potential at neuromuscular junction, whilst at synapse only occurs when EPSP reaches threshold
NMJ always excitatory, synapses can be either