Nervous system basics

Question 1

What is the cellular composition of neural tissue?

Answer 1

c. 10% neurones and 90% glial cells for support

Question 2

What are the CNS macroglia?

Answer 2

Astrocytes = support, ECM, act as phagocytes, break down glucose, form BBB

Oligodendrocytes = myelination c. 250 axons per cell

Ependymal cells = line the ventricles and spinal canal, CSF circulation

Question 3

What are the PNS macroglia?

Answer 3

Schwann cells = myelination

Satellite cells = physical support

Question 4

What are the roles of microglial cells?

Answer 4

Inflammation and immunity
Can act as phagocytes
Only seen in CNS during inflammatory insult

Question 5

Describe the structure of a neurone:

Answer 5

Cell body (4-120 micrometer diameter)
Axon

Question 6

What are the contents of a neural cell body and their roles?

Answer 6

Nucelus
Golgi bodies
Nissl substance = protein synthesis

Question 7

Describe the structure of a nerve:

Answer 7

Axon surrounded by endonuerium
Bundle of axons = fascicle
Fascicle surrounded by perineurium
Whole nerve surrounded by epineurium

Question 8

What is the reaction of a nerve to being severed?

Answer 8

Proximal section heals and forms a nerve stump
Distal section is unsupported so undergoes wallarian degeneration
Cell body puffs up, nissl substance disappears=
Chromatolyisis can be seen