The Brain, Meninges And CSF

Question 1

What is the CNS covered by?

Answer 1

The meninges- a layer of tissue which physically separates the CNS from the rest of the body.

Question 2

What are the 3 layers of the meninges?

Answer 2

Pia mater- adherent to the brain and dips down into the sulci of the brain.
Arachnoid mater- in the middle.
Dura mater- the outermost and very tough layer.

Question 3

What does the combination of the meninges and CSF do?

Answer 3

Cushion the brain and protect it from damage.

Question 4

How is the CSF produced?

Answer 4

By specialised epithelium (choroid plexus) lining cavities within the brain.

Question 5

What are ventricles?

Answer 5

Spaces or cavities within the brain linked by passageways called aqueducts. These allow CSF to circulate through the brain and open onto the surface of the CNS or into the central canal of the spinal cord.

Question 6

What does the choroid plexus secrete into ventricles?

Answer 6

Components of blood plasma, producing a clear fluid that is lower in proteins, cells and most ions than plasma.

Question 7

Which ions does the CSF have a high concentration of?

Answer 7

Sodium, magnesium and chloride.

Question 8

Where is CSF reabsorbed into the venous circulation?

Answer 8

Arachnoid granulations.

Question 9

What does an increased number of leukocytes within the CSF indicate?

Answer 9

Infection such as meningitis.

Question 10

What does an increased number of erythrocytes within the CSF indicate?

Answer 10

Brain haemorrhage or stroke.