1.1.1 Background and basic terminology

Question 1

What are the basic components of the CNS?

Answer 1

Cerebral hemispheres
Brainstem and cerebellum
Spinal cord

Derived from neural tube

Question 2

What are the basic components of the PNS?

Answer 2

Dorsal and ventral roots
Spinal nerves
Peripheral nerves
Cranial nerves (I and II are CNS)
Cauda equina (has dorsal and ventral roots, not spinal cord)

Primarily derived from neural crest cells

Question 3

What happens when a spinal nerve becomes stretched?

Answer 3

Certain injuries can cause spinal nerves to become stretched, as spinal nerves repair poorly damage can be long-lasting

Question 4

What are the two different matters within the CNS?

Answer 4

Grey matter
White matter

Question 5

What is grey matter made of?

Answer 5

Composed of:
* Cell bodies
* Dendrites

Highly vascular structure which reflects its computational role (how we understand)

Question 6

What is white matter made of?

Answer 6

Composed of axons with their supporting cells

Question 7

What causes the appearance of grey and white matter?

Answer 7

Grey- less myelin, more blood vessels

White-lots of axons, myelination is lipid based- the fat gives it the white colour

Question 8

Does grey matter have axons?

Answer 8

Yes, does not have as much as the white matter, axons are used to communicate with white matter

Question 9

What is the PNS equivalent of grey and white matter?

Answer 9

Grey matter- ganglion (collection of cell bodies)
White matter- peripheral nerve

Question 10

What is the difference between oligodendrocytes and schwann cells?

Answer 10

Oligodendrocytes are responsible for myelination within the CNS and can myelinate mutliple axons

Schwann cells are responsible for myelination in the PNS, can only myelinate single axons

Question 11

What is a nucelus within the CNS?

Answer 11

Collection of functionally related cell bodies
Grey matter structure

Question 12

What is a cortex within the CNS?

Answer 12

Folded sheet of cell bodies found on the surface of a brain structure

Typically 1-5mm thick

Grey matter structure

Question 13

What is a fibre within the CNS?

Answer 13

Axon in association with its supporting cells same meaning as ‘axon’

White matter structure

Question 14

What are the 3 types of fibres found within the CNS?

Answer 14

Association fibres
Commissural fibres
Projection fibres

Question 15

What do association fibres do?

Answer 15

Connect cortical regions within the same hemisphere

Does not cross the midline

Question 16

What do commissural fibres do?

Answer 16

Connect left and right hemispheres or cord halves

Also links left and right side of the spinal cord

Corpus callosum is an example of a commissural fibre

-issural sounds similar to fissure which splits into left and right

Question 17

What do projection fibres do?

Answer 17

Connect the cerebral hemispheres with the cord/brainstem and vice versa

Carry information longitudinally