8.2

Question 1

What protects the CNS?

Answer 1

The skeleton
Meninges
Cerebrospinal fluid
Blood brain barrier

Question 2

What is the structure of meninges?

Answer 2

Dura mater (loose covering of the brain, 2 layers- periosteal, meningeal)
Arachnoid matter (filament projections, CSF reabsorption site)
Pia Mater (Adheres to the surface of the brain)

Question 3

What are the protective coverings of the spinal cord?

Answer 3

Dura mater (outer layer, dense irregular CT)
Arachnoid matter (delicate layer of CT, blood vessels)
Pia mater (inner layer, sticks to the spinal cord surface

Question 4

What is cerebrospinal fluid?

Answer 4

Clear colourless fluid surrounds the brain and spinal cord

Question 5

What is the function of cerebrospinal fluid?

Answer 5

Mechanical protection: buoyancy, shock absorber/liquid cushioning.
Nourishment: oxygen, glucose
Regulation: exchange of nutrients, removal of wastes, communication

Question 6

How is cerebrospinal fluid produced?

Answer 6

• by ependymal cells (choroid plexus in the ventricles
• 500ml per day
  Entire volume is replaced every 8 hour
• 80-150ml in circulation
• flows through the ventricles of the brain and down the spinal canal.

Question 7

What is the purpose of the blood brain barrier?

Answer 7

Control of the CNS homeostasis
- selective permeable membrane
- regulator of transport
- mediator of communication
- protector of the CNS

Question 8

What is the blood brain barrier made up of?

Answer 8

• endothelial cells (tight junctions)
• pericytes
• basement membrane
• Astrocytes (podocytes)