Phys - Cerebral Vasculature and Brain Homeostasis Flashcards Preview

Maddy - Neuro II - tracks > Phys - Cerebral Vasculature and Brain Homeostasis > Flashcards

Flashcards in Phys - Cerebral Vasculature and Brain Homeostasis Deck (51)
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1

three locations of CSF

ventricles
cisterns
subarachnoid space

2

what are the receptors on the apical membrane of a choroid plexus cell

Na/K ATPase
aquaporin channel
NKCCl
HCO3- channels
anion channels

3

what are the receptors on the basolateral membrane of a choroid plexus cell

Na+ dependent Cl-/HCO3- exchanger (NCBE)
aquaporin channel

4

describe how sodium travels through a choroid plexus cell and what is its significance

enters cell through NCBE --> actively pumped out via Na/K ATPase

- creates a transmembrane gradient that allows movement of other ions like HCO3- and Cl-

5

how does HCO3- travel through a choroid plexus cell

HCO3- accumulates intracellularly from continuous hydration of CO2 by carbonic anhydrase --> the gradient drives HCO3- out of the cell into the ventricles down its concentration gradient through anion channel and HCO3- channels

6

how does Cl- travel through a choroid plexus cell

Cl- accumulates intracellularly from following Na+ into the cell --> creates electrochemical gradient --> leaves cell via NKCCl channel

7

what drives water from the blood into the ventricles

the osmotic gradient created by movement of Na+, Cl-, and HCO3- drives water in the same direction across apical membrane

8

how does water travel through choroid plexus cell

aquaporin channels on both basolateral and apical membranes

9

compare sodium and osmolarity between CSF and serum

about the same levels

10

compare Cl-, CO2, and pH between CSF and serum

CSF has more Cl- and CO2 than serum and a lower pH (7.33)

11

compare protein, glucose, K+, Ca2+, Mg2+, and HCO3- between CSF and serum

serum has more protein, glucose, K+, Ca2+, Mg2+, and HCO3- than CSF

12

if intracranial pressure is less than 68 mm CSF, how does this affect absorption

no absorption occurs if ICP is less than 68 mm CSF
(normal is 112)

13

how does carbon dioxide regulate cerebral blood flow

carbon dioxide will dissociate into carbonic acid, which which then dissociate into hydrogen, which causes vasodilation of blood vessels increasing blood flow

14

how does oxygen regulate cerebral blood flow

sensing of decreased oxygen causes vasodilation to increase blood flow

15

how do astrocytes regulate cerebral blood flow

the metabolites they release have vasodilator activities which increases blood flow

16

how does metabolic activity in the brain regulate cerebral blood flow

metabolic activity increase blood flow to the area of the brain that is functioning for that activity

17

when systemic cardiac output increases, what autonomic system turns on in the brain

sympathetics turn on to vasoconstrict

18

when systemic cardiac output decreases, what autonomic system turns on in the brain

parasympathetics turn on to vasodilate

19

what NT and receptors are used by sympathetics in the brain

NE and NPY
alpha-adrenergic receptors

20

what NT are used by parasympathetics in the brain

Ach, VIP, NO

21

what NT are used in sensory innervation to the blood vessels of the brain

SP, NKA, CGRP

22

why does decreased CSF cause pain
- what does the brain do to stop the pain

it renders the brain heavier, so simple motion torques the blood vessels which causes pain
- sensory afferents activate vasodilation to increase blood flow and CSF volume

23

how are ICP and cerebral blood flow related

as ICP increases, cerebral blood flow greatly decreases

24

how are PaCO2 and cerebral blood flow related

as PaCO2 increases, cerebral blood flow increases

25

how are PaO2 and cerebral blood flow related

- if O2 is too low, cerebral blood flow increases
- as O2 increases cerebral blood flow remains the same
- if O2 gets too high, cerebral blood flow decreases

26

how are cerebral perfusion pressure and blood flow related

- when cerebral perfusion pressure is low, cerebral blood flow is low
- cerebral perfusion pressure increases without change in cerebral blood flow (plateaus)
- if cerebral perfusion pressure gets too high, cerebral blood flow also begins to increase again

27

autoregulation of cerebral blood flow in times of increasing blood pressure is mediated by _____

sympathetic stimulation

28

what is the process that occurs in the event of decreased brain perfusion

activation of vasomotor centers that monitor perfusion at all times --> increase systemic blood pressure --> drives blood to the brain

29

what is the effect of anemia on cerebral blood flow

increases it

30

what is the effect of polycythemia on cerebral blood flow

decreases it