Cerebral vasculature and brain homeostasis

Question 1

step 1 of water –> ventricles process

Answer 1

Na-K-ATPase creates an electrochemical gradient for Na

Question 2

Final Result of water –> ventricles process

Answer 2

Net flux of Na, HCO3, and Cl from blood, crosses epithelium, into ventricles

creates the osmotic gradient that drives water into ventricles

Question 3

CSF ~ Serum

Answer 3

Na

osmolarity

Question 4

CSF > Serum

Answer 4

Cl-
CO2
pH is more acidic (~7.33)

Question 5

CSF < Serum

Answer 5

Protein
Glucose
pH is more basic (~7.41)
K
Ca
Mg
HCO3

Question 6

Glut 1 and where?

Answer 6

transports glucose from blood
NOT insulin dependent
2 isoforms:
   45kD - astrocytes
   55kD - microvessels, choroid plexus, ependymal cells

Question 7

Na-K-2Cl

Answer 7

transports ions from CSF to blood
Expression tied to endothelin 1 & 3
Endothelin prod. tied to astrocyte signals; may be related to [K] in CSF

Question 8

P-glycoprotein

Answer 8

“bouncer”
Moves drugs that dont belong that crossed BBB back into blood
Similar to MRP1 in GI
member of ATP-binding casette transporter family

Question 9

GLUT3 where?

Answer 9

Neurons

Question 10

GLUT5 where?

Answer 10

Microglia

Question 11

Circumventricular organs

Answer 11

Posterior pituitary (secretory)
Area postrema (sensory)
organum vasculosum of the lamina terminalis (sensory)
subfornical organ (sensory)

Question 12

Area postrema

Answer 12

sensory

initiation of vomiting in response to chemotactic triggers

Question 13

Organum vasculosum of the lamina terminalis (OVLT)

Answer 13

sensory

regulation of total body water and thirst – target of AGT2