CSF (Quiz 5)

Question 1

CSF is formed within the ventricles, fills them, and emerges from the apertures in the _____ ventricle to fill the subarachnoid space

Answer 1

4th

Question 2

What are the functions of CSF?

Answer 2

-suspension of the brain through its partial floatation
-regulates the composition of the fluid bathing the neurons and glial cells
-transport hormones
-acts as buffer
-removes wastes
-provides a fluid through which chemical messengers can be widely distributed in the NS
-immunity during development (contains a lot of macrophages)
-secretes growth factors during development
-produces insulin (only other place in the body that does this is the pancreas)
-expresses ACE2 receptors which is how covid enters into cells

Question 3

The choroid plexus is a ____________ tissue found in each ventricle, the main function of which is to produce CSF

Answer 3

secretory

Question 4

The choroid plexus consists of _______________ epithelial cells surrounding a core of fenestrated capillaries and connective tissue

Answer 4

simple cuboidal

Question 5

The choroid plexus forms the _____________ barrier. Tight junctions between adjacent epithelial cells restrict the free diffusion of solutes from blood into CSF. This barrier prevents harmful substances from entering the brain while also allowing harmful waste to exit back into the bloodstream. Water is allowed to pass the barrier and is used to manufacture CSF

Answer 5

blood CSF

Question 6

Lining each ventricle are ______________ cells overlain by a layer of pia mater.

Answer 6

ependymal

Question 7

At certain locations the _______________ complex invaginates into the ventricle with a collection of capillaries. At these ventricular locations the ependymal layer is specialized as a cuboidal secretory epithelium called the ____________ epithelium.

Answer 7

pia-ependyma, choroid

note: the ependyma-pia-capillary complex is the choroid plexus

Question 8

The choroid plexus is functionally a ______ layered membrane between blood and CSF

Answer 8

3

Question 9

The choroid plexus is functionally a 3 layered membrane between blood and CSF. What is the first layer?

test q

Answer 9

-endothelial wall of each choroidal capillary
-this wall is fenestrated and allows for easy movement of substances out of the capillary

Question 10

The choroid plexus is functionally a 3 layered membrane between blood and CSF. What is the 2nd layer?

test q

Answer 10

consists of scattered pial cells and some collagen fragmentally

Question 11

The choroid plexus is functionally a 3 layered membrane between blood and CSF. What is the 3rd layer?

test q

Answer 11

-choroid epithelium
-choroid epithelial cells are specialized for secretion with basal infoldings, microvilli, on the side facing the CSF, and abundant mitochondria
-adjacent cells are connected to one another by arrays of tight junctions, these junctions help limit the movement of substances across the choroid epithelium (note: some ions can diffuse across tight junctions, but peptides and other larger molecules are blocked)

Question 12

What takes up 2/3 of the total ventricular SA?

Answer 12

choroid plexus

Question 13

CSF is formed by filtration of blood through the fenestrations of the choroidal capillaries, followed by the active transport of substances. It was thought to be an ultrafiltrate of blood, but this cant be true because…..

*** just need to memorize 1 bullet point

Answer 13

-CSF contains a higher conc. of magnesium and chloride ions and a lower conc. of potassium and calcium ions. These concentrations are maintained at very stable levels even when plasma levels fluctuate
-CSF formation can be reduced by certain metabolism inhibitors, showing it is an active, energy requiring process

Question 14

What are the main arteries that supply the choroid plexus?

Answer 14

1) choroidal a.
2) internal carotid a.
3) anterior and posterior inferior cerebellar arteries

Question 15

CSF is a clear fluid produced by the choroid plexus at a rate of __________ mL/day

Answer 15

500-700

Question 16

How much CSF is currently circulating in the ventricles and subarachnoid space?

Answer 16

150mL

Question 17

The production of about 500mL of CSF a day means that it is turned over/replaced ________x a day

Answer 17

3-4

Question 18

Formation of CSF is constant and little is affected by….

Answer 18

systemic BP or intraventricular pressure

Question 19

60-75% of CSF is produced by the choroid plexus of the….

Answer 19

lateral, 3rd, and 4th ventricles

Question 20

What happens if someone is chronically stressed and is constantly running on cortisol?

Answer 20

over time they will decrease CSF by 30%

Question 21

There is a long, continuous band of choroid plexus following the C-shaped course of the ___________ ventricle. It extends from near the tip of the inferior horn, through the body of the ventricle reaching the interventricular foramen. The plexus is enlarged in the atrium of the ventricle and is called the __________

Answer 21

lateral, glomus

Question 22

The choroid plexus of each lateral ventricle grows through the interventricular foramen, forming part of its posterior wall, and becomes the 2 narrow stands of choroid plexus in the ____________________ ventricle. It does not continue through the cerebral aqueduct

Answer 22

roof of the 3rd

Question 23

The choroid plexus of the 4th ventricle is formed from an invagination of the _______________________. The strands of plexus in the 4th ventricle extend as far as the median aperture

Answer 23

inferior medullary velum

Question 24

CSF is turned over 3-4x a day. It continually circulates from its site of formation to a site of removal. It is removed through villi to sinuses to….

Answer 24

IJV

Question 25

CSF is formed in the lateral ventricles and passes through the interventricular foramina into the 3rd ventricle. From the 3rd ventricle, CSF goes through the cerebral aqueduct into the 4th ventricle. Through the median and lateral apertures into the _____________ and the ________________- then the subarachnoid space. From these basal cisterns, CSF moves through the tentorial notch, up and over the cerebral hemispheres, through the arachnoid villi, and into the superior sagittal sinus

Answer 25

cisterna magna, pontine cistern

Question 26

_________________________________________ cause a constant ebb and flow, with a small net movement toward the superior sagittal sinus with each heartbeat. The subjects posture and jugular venous pressure also modulate CSF flow dynamics and pressure

Answer 26

Arterial pulsations, respiratory movements, and vasomotor activity

Question 27

CSF is absorbed into the dural venous sinuses via the….

Answer 27

arachnoid granulations

Question 28

What is the circulation of CSF pathway?

Answer 28

2 lateral ventricles > 2 interventricular foramen (foramen of monro)> 3rd ventricle> aqueduct of sylvius (cerebral aqueduct)> 4th ventricle> 2 foramen lushka (lateral apertures), 1 foramen of magendie (median aperture), and central canal> subarachnoid space> arachnoid villi> superior sagittal sinus> venous space> IJV> SVC> heart> choroid plexus of lateral ventricle and repeat