Ventricles and CSF Circulation (6A part 3)

Question 0

Through what do the lateral ventricles communicate with the midline third ventricle?

Answer 0

Interventricular foramen of Monro

Question 1

What four structural components does each lateral ventricle have?

Answer 1

1. Anterior (frontal) horn
2. Body
3. Inferior (temporal) horn
4. Posterior (occipital) horn

Question 2

Via what structure do the third and fourth ventricles communicate?

Answer 2

Cerebral aqueduct (of Sylvius)

Question 3

Via what 2 openings does CSF leave the fourth ventricle?

Answer 3

1. Foramen of Luschka (lateral aperture)

2. Foramen of Magendie (median aperture)

Question 4

What is the main difference in the composition of CSF compared to that of plasma?

Answer 4

CSF has much lower levels of protein compared to plasma

Question 5

Where does most CSF fluid go once it drains out of the 4th ventricle?

Answer 5

Most travels upward through the opening in the tentorium cerebelli and circulates over and around the brain, all within the subarachnoid space. Some circulates down around the spinal cord.

Question 6

Where is the vast majority (90%) of CSF reabsorbed and where does it go once reabsorbed?

Answer 6

Reabsorbed in the arachnoid granulations (arachnoid villi) into venous sinuses. Granulations/ villi act as one-way valves that let CSF out but not in(similar to lymph drainage)
(10% is reabsorbed in the spinal cord at the points the nerve roots exit the spinal cord)

Question 7

Where is CSF made? What kind of cells do it?

Answer 7

Made in the choroid plexus by specialized epithelial cells that line the lateral, third, and fourth ventricles

Question 8

What is the clinical term for hydrocephalus caused by blockage of outflow from the ventricular system?

Answer 8

Obstructive hydrocephalus

Question 9

What is the appropriate clinical term for hydrocephalus caused by a blockage of the arachnoid villi/granulations?

Answer 9

Non-obstructive hydrocephalus

Question 10

What exactly is an arachnoid villi?

Answer 10

Outpouchings of arachnoid mater into venous sinuses

Question 11

What structure is found between the bodies of the two lateral ventricles in the midline?

Answer 11

Fornix

Question 12

What structure lies just superior to the bodies of the lateral ventricles?

Answer 12

Corpus callosum

Question 13

What structures lie just lateral to each lateral ventricle?

Answer 13

Body of caudate nucleus (of the basal ganglia)

Question 14

What structures lie just inferior and slightly medial to the inferior (temporal) horn of the lateral ventricles? (Both structures are paired, so seen on right and left sides of brain)

Answer 14

Hippocampus/ dentate gyrus (gyrus is a part of hippocampus, is slightly more medial than hippocampus proper)

Question 15

What structure lies just superior and slightly medial to the inferior (temporal) horn of each lateral ventricle? (Again, each of these structures is paired so happens on both sides)

Answer 15

Tail of caudate nucleus (of the basal ganglia)