Cerebrospinal fluid and blood brain barrier

Question 1

what 3 structures help stabilize neurons in the CNS?

Answer 1

BBB, choroid plexus, CSF

Question 2

what is continuous with CSF?

Answer 2

interstitial fluid

Question 3

what contains the brain?

Answer 3

cranial meninges

Question 4

what are the 3 layers of the crainal meninges?

Answer 4

dura matter
arachnoid matter
pia matter

Question 5

which layer of the meninges has CSF?

Answer 5

arachnoid mater

Question 6

what are the series of chambers in the CNS called?

Answer 6

ventricles

Question 7

what are ventricles filled with?

Answer 7

CSF and ependymal cells

Question 8

how many ventricles are there?

Answer 8

two lateral ventricles
third ventricle
4th ventricle

Question 9

how are the ventricles connected in the brain and spinal cord?

Answer 9

brain - aqueducts
spinal cord - central canal

Question 10

what are ependymal cells?

Answer 10

line brain surface, ventricles, and choroid plexus

Question 11

what are the 3 main functions of ependymal cells in the CNS?

Answer 11

1. proliferation -> stem cells -> new neurons and glial cells in brain
2. produce CSF from plasma
3. form and circulate CSF

Question 12

what can disrupting the movement of the cilia on the brain do?

Answer 12

affect movement of CSF

Question 13

what is the circulation of CSF

Answer 13

intraventricular foramina -> third ventricle -> cerebral aqueduct -> forth ventricle -> lateral and median apertures -> subarachnoid space -> arachnoid granulations in superior sagittal sinus -> venous circulation

Question 14

where does removal of CSF occur?

Answer 14

sagittal sinus

Question 15

how is CSF removed through the sagittal sinus?

Answer 15

CSF absorbed across arachnoid villi into venous circulation by drainage into lymphatic vessels

Question 16

where is the dorsal sagittal sinus located?

Answer 16

between two hemispheres of the brain

Question 17

is the removal of CSF pressure dependent - how?

Answer 17

yes - pressure of CSF is greater than low pressure venous system

Question 18

what does the pressure difference between the CSF and venous system create?

Answer 18

bulk one-way flow of fluid

Question 19

what is hydrocephalus?

Answer 19

increased CSF volume in skull associated with increased intracranial pressure

Question 20

what is non-communicating hydrocephalus?

Answer 20

blockage of CSF movement through cerebral aqueduct or lateral/media apertures

Question 21

what is another name for non-communicating hydrocephalus?

Answer 21

internal hydrocephalus

Question 22

what is communicating hydrocephalus?

Answer 22

impairment of absorption into the dorsal sagittal sinus

Question 23

what is another name for communicating hydrocephalus?

Answer 23

external hydrocephalus

Question 24

what is a treatment for hydrocephalus?

Answer 24

ventriculo-peritoneal shunt

Question 25

where is the pressure increasing in internal hydrocephalus?

Answer 25

ventricles expand -> pressure inc

Question 26

where is the pressure increase in external hydrocephalus?

Answer 26

outside of the brain

Question 27

what are the two locations of a spinal tap?

Answer 27

cisterna magna subarachnoid space in lumbar spina column

Question 28

when collecting CSF for a suspected lesion where do you collect?

Answer 28

whichever site it closest to the suspected lesion

Question 29

which is riskier cisterna magna or lumbar spinal column for a spinal tap?

Answer 29

cisterna magna - risk of cerebella herniation

Question 30

what does CSF analysis asses?

Answer 30

inflammatory processes

Question 31

what is CSF formed by?

Answer 31

choroid plexus

Question 32

what is formed by selective movement of solutes across BBB?

Answer 32

CSF and brain interstitial fluid

Question 33

what creates the osmotic gradient for water to be taken into the CSF?

Answer 33

inward flux of Na, HCO3, and Cl

Question 34

what are the components of the BBB?

Answer 34

endothelial cells basement membrane glia

Question 35

what are the cell to cell connections in the BBB?

Answer 35

tight junction adherence junctions desmosomes

Question 36

what is the BBB ineffective against?

Answer 36

substances that can diffuse through the plasma membrane ex. steroid

Question 37

Brain capillaries consist of ________ linked by _________ that interact with ________ and _________ to selectively control movement of materials into the brain

Answer 37

Brain capillaries consist of **endothelial cells** linked by **tight junctions** that interact with **astrocytes** and **pericytes** to selectively control movement of materials into the brain

Question 38

where is the BBB absent?

Answer 38

certain areas that need to monitor chemical composition of blood and release hormones to the body - vomiting center and hypothalamus

Question 39

what are the selective entry mechanisms of the BBB?

Answer 39

diffusion of lipid soluble substances receptor mediated transport

Question 40

what are lipid soluble substances that can diffuse into the brain?

Answer 40

ketone bodies - energy source for brain during starvation CO2 - inc protein conc. in brain interstitial fluid

Question 41

what is responsible for low level basal glucose uptake into the BBB in endothelial cells and astrocytes?

Answer 41

GLUT1

Question 42

what is a high affinity isoform that is main present in neurons that will facilitate movement of glucose?

Answer 42

GLUT3

Question 43

what is P-glycoprotein?

Answer 43

transports large lipophilic molecules out of CSF

Question 44

what is another name for P-gp?

Answer 44

MDR1

Question 45

what drug temporarily inhibits the BBB?

Answer 45

amitriptyline

Question 46

what are macrocyclic lactones?

Answer 46

avermectins and milbemycins broad antiparasitic

Question 47

why cant collies have ivermectin?

Answer 47

MDR1 has a mutation that allows ivermectin pass BBB -> ivermectin binding to GABA channels impairing signaling -> neurological symptoms

Question 48

compare CSF and blood serum

Answer 48

low K+ and fewer larger proteins similar osmolarity