Ventricles and CSF

Question 1

Where is CSF made?

Answer 1

Choroid Plexus of the Lateral, 3rd and 4th Ventricles…made by specialized epithelial cells

Question 2

CSF escapes the lateral ventricles into the 3rd ventricle via

Answer 2

the Foramen of Monro….then goes into the 4th via the aqueduct of Sylvius and leaces the fourth ventricle via the foramina of magendie (Median) and Luschaka (lateral)

Question 3

Once out in the subarachnoid space, where does the CSF go?

Answer 3

The bulk of it travels upward through the opening in the tentorium cerebelli and circulates over and around the brain. It is then reabsorbed into the venous sinuses via the arachnoid granulations.

About 10% of it travels down around the spinal cord where it is then reabsorbed at the egress point of the nerve roots.

Question 4

Obstruction of the outflow pathways (routes through which CSF may leave the subarachnoid space) and/or blockage of the pathways between the ventricles may cause what

Answer 4

Buildup of CSF and hydrocephalus

Question 5

What is the secret to the BBB

Answer 5

Tight Junctions

Question 6

What differentiates ventricular ependymal cells from choroid epithelium?

Answer 6

Ventricular ependymal cells possess the normal fenestration between adjacent cells while the choroid epithelial cells are tightly approximated to one another in so-called tight junctions

Question 7

What 3 things is drug absorption across the blood brain barrier dependent on?

Answer 7

Lipid solubility, molecular weight, whether or not the drug is a substrate for the multidrug nonspecific transporter in the apical membranes of the endothelial cells.

Question 8

Realize that drugs with high lipid solubility have a short duration of clinical action because they are so rapidly redistributed from their main site of action to non-active sites. They do, however, take a long time to eliminate because they sit in non-active fat stores.

Answer 8

ok

Question 9

What is the choroid plexus

Answer 9

Its created by an outpouching of capillaries and pia mater into ventricular space…Basically, the choroid plexus sandwiches capilary blood vessels between layers of arachnoid and pia

Question 10

Circumventricular organs?

Answer 10

Brain areas which function to monitor and regulate fluctuations in blood chemistry and therefore require rapid access to blood. They typically line the ventricular system and are thus called circumventricular organs.

Question 11

WHat is one circumventricular organ to know

Answer 11

organum vasculosum- monitors and regulates electrolyte balance and several important hormones.