Ventricles and Cerebrospinal Fluid

Question 1

Ventricles

Answer 1

Interconnected brain cavities that produce, store and circulate cerebrospinal fluid (CSF)

2 lateral ventricles, 1 third ventricle and 1 fourth ventricle

Question 2

Choroid Plexus

Answer 2

CSF produced by choroid plexus (Ependymal cells make the choroid plexus) – CSF fluid replaced 3x daily

Function of CSF:

1. Cushions the brain
2. Provides Nutrients
3. Waste-Product Removal

Question 3

Lateral Ventricles

Answer 3

Two, C-shaped ventricles

Roof composed of fibers of corpus collosum; floor the superior surface of thalamus

Consists of the central body and three extensions:

1. anterior
2. posterior (occipital) horns
3. inferior (temporal) horns

Question 4

Third Ventricle

Answer 4

Narrow vertical space between the two thalami; floor hypothalamic nuclei; proximal to brainstem

Rostrally connected to lateral ventricles by interventricular foramen of Monro

Narrows to become the cerebral aquaduct, which connects to the fourth ventricle

Question 5

Fourth Ventricle

Answer 5

Cerebellum forms roof; Pons and medulla create triangular floor; CN V - CN XII directly beneath the ventricle

Three openings for CSF to fill subarachnoid space at widest point:
2 lateral: foramina of Luschka
1 medial: foramen of Magendie

Question 6

Problems in Ventricles

Answer 6

When there is a blockage in movement or decrease in ability to reabsorb CSF, ventricles enlarge and CSF pressure increases

Swelling from excess CSF fluid comes from all around the brain; from the ventricles themselves, but also from the fluid between brain and skull; compression from all surrounding areas

Some Causes: hydracephalus, intracranial tumor, hemorrhage, excess production of CSF, meningitis or encephalitis

Diff btwn encephalitis and meningitis: encephalitis infection/inflammation of actual brain tissue; meningitis infection/inflammation of the meninges; men can lead to en; both can co-occur

Question 7

Role of CSF

Answer 7

Pressure differential helps regulate the flow of CSF;

Dry brain weighs around 1100-1200g; CSF causes bouyancy; brain weight can be around 75g; skull is not smooth, and cranial nerves can be compressed w/o the fluid

CT and MRI detect bleeding; cannot detect axonal injury

Once blood touches neurons, they die; immediate necrosis