Cerebral Vasculature and Brain Homeostasis

Question 1

On what side of the choroid plexus cell is the Na-K ATPase expressed?

Answer 1

Apical side

Question 2

On what side of the choroid plexus is the NCBE (Na-Cl-Bicarb Exchanger) expressed?

Answer 2

Basolateral (blood)

Question 3

What creates the osmotic gradient that drives water into ventricles?

Answer 3

Net flux of Na+, Cl-, and HCO3- from blood into ventricles

Question 4

What is the pH of CSF relative to blood?

Answer 4

Acidic

Question 5

What does blood contain more of than CSF?

Answer 5

Protein

Glucose

K+, Ca2+, Mg2+, HCO3-

Question 6

What does CSF contain more of than blood?

Answer 6

Cl-

CO2

Question 7

How does intracranial pressure affect CSF?

Answer 7

Low ICP => No CSF absorption (maintain homeostatic pressure)

High ICP => High CSF absorption (proportional relationship)

CSF production remains constant

Question 8

Why does increased CO2 in blood increase cerebral blood flow?

Answer 8

Increased [CO2] causes increased H+ which causes vasodilation => increased blood flow => Increased O2 concentration

Question 9

750-900 mL/min

Answer 9

What is the normal rate of cerebral blood flow?

Question 10

What autonomic system is activated when CO or BP increase? What is its action?

Answer 10

Sympathetic

Vasoconstriction

Question 11

What are the cerebral sympathetic NTs?

Answer 11

NE, NPY

Question 12

What autonomic system is activated when CO or BP decrease?

Answer 12

Parasympathetic

Vasodilation

Question 13

What are the cerebral parasympathetics NTs?

Answer 13

ACh, VIP, CGRP, SP

Question 14

What are the NTs released in response to sensory cerebral innervation?

Answer 14

SP, NKA, CGRP

Question 15

What is the effect of polycythemia on cerebral blood flow?

Answer 15

Decreased (increased blood viscosity slows blood flow)

Question 16

What is the effect of anemia on Cerebral Blood Flow?

Answer 16

Increased

Question 17

What is the effect of acidosis on CBF? Alkalosis?

Answer 17

Acidosis: Increased CBF

Alkalosis: Decreased CBF

Question 18

What are the BBB and the blood-CSF barriers nearly impermeable to?

Answer 18

Plasma proteins

Non-lipid-soluble organic molecules

Question 19

What cells comprise the blood-brain barrier?

Answer 19

Astrocyte endfeet

Pericytes

Endothelial cell

Question 20

What neural cells use the 45kD isoform of Glut1?

Answer 20

Astrocytes

Question 21

What neural cells use the 55kD isoform of Glut1?

Answer 21

Microvessels

Choroid plexus

Ependymal cells

Question 22

What neural cells use Glut3?

Answer 22

Neurons

Question 23

What neural cells use Glut5?

Answer 23

Microglia

Question 24

What is the transporter that actively moves harmful substances that have crossed the BBB back into the blood?

Answer 24

P-glycoprotein

Question 25

Expression of the NaKCC transporter is tied to what peptides?

Answer 25

Endothelin 1 and 3

Question 26

What are the circumventricular organs?

Answer 26

1. Posterior pituitary
2. Area Postrema
3. Organum Vasculosum of the Lamina Terminalis (OVLT)
4. Subfornical organ

Question 27

What are the sensory CVOs?

Answer 27

Area postrema - initiate vomiting

OVLT - regulate body water and thirst

Subfornical organ

Question 28

What is significant about the CVOs?

Answer 28

No BBB or blood-CSF barrier