CSF - Lecture 3

Question 1

what is CSF

Answer 1

watery “broth” found in and around the brain and spinal cord

Question 2

what does CSF form

Answer 2

a liquid cushion

gives buoyancy to the CNS organs

Question 3

what happens with the brain floating

Answer 3

CSF reduces brain weight by 97%

prevents the brain from crushing under its own weight

Question 4

what does the CSF also do

Answer 4

protects the brain and spinal cord from trauma

Question 5

what does the CSF help with

Answer 5

nourish the brain

remove wastes produced by by neurons

Question 6

what does CSF carry

Answer 6

chemical signals b/w different parts of the CNS

Question 7

how much CSF is in the body

Answer 7

100-160 mL of fluid present in the body at one time

Question 8

normal total volume of CSF

Answer 8

150 cc

Question 9

what is CSF produced by

Answer 9

choroid plexus

@ a rate of about 20 cc per hour or 500 cc per day

Question 10

how often is CSF changed

Answer 10

every 6-7 hours

Question 11

what is the composition of CSF

Answer 11

similar to blood plasma

contains less protein and more sodium and chloride ions

Question 12

how is CSF formed

Answer 12

cells actively secrete Na+ into the ventricular system in exchange for K+

sodium ions electrically attract Cl- and osmotically draw water from the blood vascular system to constitute CSF

Question 13

where is most CSF formed

Answer 13

choroid plexus

membranes on the roofs of the four brain ventricles

Question 14

where is the choroid plexus

Answer 14

hangs from the roof of each ventricle

Question 15

what are the plexuses

Answer 15

clusters of thin walled capillaries

enclosed by a layer of ependymal cells

Question 16

capillaries of the choroid plexus

Answer 16

fairly permeable

fluid filters continuously from the bloodstream into the ventricles

Question 17

how are the cells in the choroid plexus joined

Answer 17

tight junctions

Question 18

choroid plexus cells also have

Answer 18

ion pumps

allow them to modify filtrate by actively transporting only certain ions across their membranes into the CSF pool

Question 19

what happens to CSF after it enters the ventricles

Answer 19

moves freely throughout the choroid plexuses

Question 20

some CSF enters ______

Answer 20

canal of the spinal cord

Question 21

where does most CSF go

Answer 21

enters the subarachnoid space through the lateral and median apertures in the walls of the fourth ventricle

Question 22

what does CSF do in the subarachnoid space

Answer 22

bathes the outer surface of the brain and cord

Question 23

CSF pressure in a human

Answer 23

150-180

Question 24

what is CSF pressure regulated by

Answer 24

rate of absorption and rate of formation

Question 25

subarachnoid hemorrhages

Answer 25

block absorption

raises pressure

Question 26

congenital excessive formation or blockage to flow

Answer 26

raises pressure

Question 27

brain tumors

Answer 27

lower absorption

raise pressure

Question 28

inflamed meninges

Answer 28

can cause excessive formation and raise pressure