Lectures 11-15

Question 1

What is neuropraxis?

Answer 1

Injury to the myelin sheath (neurone can’t function)

Question 2

What is axonotmesis?

Answer 2

axpn is damaged, but endoneurium, perineurium, and epineurium remain intact.

Question 3

How does the axon heal from axonotmesis?

Answer 3

The various layers provide guidance to the nerve sprouts on where to attach

Question 4

What is neurotmesis?

Answer 4

when the entire nerve fibre is severed (complete recovery doesn’t occur)

Question 5

What happens soon after a severe neurone injury?

Answer 5

it would stop conducting AP’s, and the cut ends would leak intracellular fluid. The ends will split apart, swell, and seal

Question 6

What would happen hours after a severe neurone injury?

Answer 6

synaptic terminals degenerate
neurofilaments accumulate
astroglia cause terminals to be pulled away from the postsynaptic cell

Question 7

What happens days after a severe neurone injury?

Answer 7

Cell body of the proximal segment undergoes chromatolysis

The distal stump undergoes Wallerian Degeneration

Question 8

What is chromatolysis?

Answer 8

Cell body produces repairing hormones, injured nerve forms a neuroma seal, allowing it to regenerate

Question 9

What happens in Wallerian Degeneration?

Answer 9

distal segment dies, although protective sheathing may be preserved, leaving behind a hollow tube

Question 10

What has the degeneration of fibres allowed us to do?

Answer 10

trace neural pathways

Question 11

How would you divide the fate of a denervated muscle?

Answer 11

Acute phase

Chronic phase

Question 12

What is a Reperfusion injury?

Answer 12

crushing injury to large muscle masses, causing fluid loss, hematuria, and traumatic Rhabdomylosis.

Question 13

What are the sympathetic neurotransmitters and receptors?

Answer 13

Ganglionic, nACh(r)

Effector, alpha/beta adrenoreceptors

Question 14

What are the parasympathetic neurotransmitters and receptors?

Answer 14

ganglionic, nACh(r)

effector, mACh(r)

Question 15

Which main nerves are parasympathetic?

Answer 15

CN 3, 7, 9, 10 (only autonomic ones)

SN S2, S3, S4

Question 16

where does sympathetic outflow leave the CNS?

Answer 16

T1 to L2/L3

Question 17

What is the prevertebral chain?

Answer 17

lies anterior to the vertebral bodies in relation to the carotids

Question 18

What 3 fibres are formed from sympathetic outflow?

Answer 18

White rami (myelinated) communicans
Grey rami (unmyelinated) communicans
Splanchic nerves

Question 19

What is the difference in structure of somatic and autonomic neurones?

Answer 19

Somatic signals are more discrete, innervating specific fibres
Autonomic neurones have many swellings along the axon, each of which contains neurotransmitters in vesicles (broadcast messages)

Question 20

Why are sweat glands unusual?

Answer 20

They recieve single innervation sympathetically, but they only use nACh!

Question 21

What are the effects of SympNS and ParaNS on heart rate

Answer 21

SympNS increases

ParaNS decreases

Question 22

Which of the SympNS and ParaNS increase motility?

Answer 22

ParaNS

Question 23

Which of the dilator papillae and the constrictor papillae recieve sympathetic innervation?

Answer 23

dilator papillae

Question 24

What sort of innervation do blood vessels recieve?

Answer 24

single, sympathetic innervation

EXCEPT THOSE SUPPLYING THE HEAD AND GONADS