Peripheral Nerves Flashcards
1
Q
How can one input lead to 2 specific outputs?
Remeber PNS
A
- If sensory neuron synapses with a inhibitory interneuron
(on its way to the motor neuron)
2
Q
Which part of the spinal cord has a root ganglion?
dorsal or ventral?
A
Dorsal!
3
Q
What is the function of the perineurium/endoneurium/epineurium?
+ what they are
A
- Sheath of connective tissue
- Gives structural rigidity and flexibility
4
Q
Why does the PNS require a sheath of connective tissue - and the CNS doesnt?
A
- PNS moves a lot so it needs encasing
- CNS doesnt move
5
Q
What does a schwann cell do?
A
Surroundes every axon in the PNS
6
Q
What is this?
A
6
Q
What is a fascicle?
A
- Bundle of axons wrapped in perineurium
7
Q
What is this?
A
8
Q
What is this?
A
9
Q
What is this?
A
10
Q
What is this?
A
11
Q
What is this?
A
12
Q
What is the process of myelination?
A
- Glial cell wraps around axon
- Cytoplasm squeezed out as sheath forms
- Myelin sheath acts as insulation
13
Q
What do we call the gaps in the myelin?
A
Nodes
14
Q
How does myelination allow for fast axonal conduction?
A
- Allows ‘jumping conduction’ from node to node
16
Q
What is this?
A
17
Q
What is this?
A
18
Q
What is this?
A
19
Q
What is this?
A
20
Q
What is this?
A
22
Q
How do nerves regenerate after an axon is damaged?
A
- Schwann cells repair while SC and macrophages clean up
- Muscle accepts regenerated axon, protein synthesis occurs and axon regenerated
- Regeneration may fail if axons are unable to regenerated &muscle prevent reinnervation
