Module 2: Section 2

Question 1

4 principle protective measures for the CNS

Answer 1

1. Bone
2. Protective membranes
3. Cerebrospinal fluid
4. Blood-brain barrier

Question 2

Bone

Answer 2

The skull and vertebrae provide a hard physical barrier as protection against damage

Question 3

What protective measure surrounds the brain?

Answer 3

Skull/cranium

Question 4

What protective measure surrounds the spinal cord?

Answer 4

Veretebrae

Question 5

What are the meninges?

Answer 5

3 membranes that wrap and contain the CNS

Question 6

Names of the 3 meninges

Answer 6

1. Dura mater
2. Arachnoid mater
3. Pia mater

Question 7

Dura mater

Answer 7

• Outermost membrane
• Tough double membrane that lies next to the bone
• Usually 2 layers are in direct contact but in some regions may be separated to create the dural sinuses

Question 8

Dural sinuses

Answer 8

• Blood-filled spaces
• Blood draining from the brain empties into these sinuses to be returned to the heart
• Cerebral spinal fluid can also drain here

Question 9

Arachnoid mater

Answer 9

• Middle meninges
• Delicate and is highly vascularized

Question 10

Arachnoid granulation villi

Answer 10

• Projections of the arachnoid mater
• Penetrate through the dura and extend into the sinuses
• Allows the transfer of cerebrospinal fluid

Question 11

Subarachnoid space

Answer 11

Space between arachnoid mater and the pia mater

Question 12

Pia mater

Answer 12

• Innermost membrane
• Highly vascularized
• Tightly adheres to the surface of the brain and the spinal cord
• Certain areas it dips deeper into the brain to bring blood supply to the ependymal cells lining the ventricles

Question 13

Cerebrospinal fluid

Answer 13

• Protects brain by acting like a shock-absorber
• Located in the subarachnoid space
• Essential for the transfer of materials between the blood and neural tissues

Question 14

Chlorid plexuses

Answer 14

• highly vascularized masses of pia mater that dip into pockets of ependymal cells and create the CSF
• Found in each of the 4 ventricles

Question 15

Flow of CSF

Answer 15

• Once made it flows through ventricles & enters the subarachnoid space to circulate around the brain
  -It also flows into the spinal cord’s central canal
• Finally, CSF is reabsorbed into venous blood via arachnoid villi

Question 16

Blood-Brain Barrier

Answer 16

A selective barrier formed by brain capillary endothelial cells with tight junctions that protects the brain by blocking harmful substances while allowing nutrients in