Practical 3 - station 2 - ventricles

Question 1

What are ventricles?

Answer 1

Irregularly shaped cavities in brain containing CSF

Question 2

How many ventricles are there?

Answer 2

2 lateral
3d
4th

Question 3

Which is the largest ventricle?

Answer 3

2 asymmetrical lateral cavities

Question 4

What is the function of the interventricular foramen of Munro?

Answer 4

Allows the lateral ventricles to communicate with the 3rd ventricle

Question 5

How is the 3rd ventricle connected to the 4th ventricle?

Answer 5

Cerebral aqueduct (runs through midbrain)

Question 6

What is caudal to the 4th ventricle?

Answer 6

Medulla

Question 7

How does CSF drain into the subarachnoid space?

Answer 7

From 4th ventricle via single median and 2 lateral apertures

Question 8

How is CSF produced?

Answer 8

Secreted and continuously produced by choroid plexus of all ventricles

Question 9

What is the total CSF volume?

Answer 9

150ml

Question 10

How often is the CSF replaced?

Answer 10

Every 8 hours

Question 11

How much CSF is formed daily?

Answer 11

Approx 500ml

Question 12

What does CSF usually consist of?

Answer 12

Clear
colourless
blood plasma composition
very few cells - mostly lymphocytes

Question 13

What aspect of the CSF indicates disease?

Answer 13

> 10 cells/ml

Question 14

What are some functions of the CSF?

Answer 14

Liquid cushioning and buoyancy
Reduces brain weight by about 97% preventing it crushing under its own weight
Protects brain and spinal cord from blows and trauma
Nourishes the brain
Carries chemical signals (hormones) from one part of brain to another

Question 15

What is the weight of the brain?

Answer 15

1.3kg

Question 16

What direction does CSF flow in?

Answer 16

One way system - lateral to 3rd to 4th

Question 17

Where does CSF enter circulation?

Answer 17

Choroid plexus in all 4 ventricles so can enter at any stage

Question 18

Where does the CSF go after the 4th ventricle?

Answer 18

It can either enter the subarachnoid space via apertures or continue in the central canal of the medulla and spinal cord

Question 19

How can the CSF exert pressure on the brain?

Answer 19

If a tumour or something else obstructs its circulation

Question 20

What is hydrocephalus?

Answer 20

New born babies head enlarges as skull bones not fused and CSF blocked so exerts pressure on brain

Question 21

Why does hydrocephalus only occur in new borns

Answer 21

In adults skull is more rigid and hard so accumulating fluid compresses the blood vessels and crushes the soft nervous tissue - get brain damage instead