Background

Question 1

is CBF higher in men or women?

Answer 1

CBF higher in girls and women

Question 2

Vasoconstriction

Answer 2

Vasoconstriction (narrowing of the vessel) is caused by an increase in intracellular Ca2+ concentration within VSM cells that causes contraction.

Question 3

Vasodilation

Answer 3

vasodilation (widening of the vessel) is caused by either a decrease in intracellular calcium concentration or dephosphorylation of myosin light chain.

Question 4

a. What vasoactive substances are produced by the endothelium to regulate blood flow?

Answer 4

i. Vasodilators
Nitric oxide
Prostacyclin (PGI2)
Endothelium-derived hyperpolarization factor (EDHF)
Induce vasodilation by activating calcium-activated potassium channels in vascular smooth muscle cells

ii. Vasoconstrictors
Endothlin-1
thromboxane

Question 5

Give a few examples of Vasodilators

Answer 5

1. Nitric oxide
2. Prostacyclin (PGI2)
3. Endothelium-derived hyperpolarization factor (EDHF)
   a. Induce vasodilation by activating calcium-activated potassium channels in vascular smooth muscle cells

Question 6

Give a few examples of vasoconstrictors

Answer 6

1. Endothlin-1
2. thromboxane

Question 7

What are the 4 categories of endothelial cells

Answer 7

arterial
venous
capillary
lymphatic

Question 8

Describe venous endothelial cells

Answer 8

1. Enhanced gene expression related to inflammation and leukocyte extravasation, more enzymatic and metabolic proteins

Question 9

Describe capillary endothelial cells

Answer 9

1. Enhanced gene expression for structural and transport proteins (BBB function)

Question 10

c. How does aging affect the vascular endothelial cells?

Question 11

Describe myoendothelial projections

Answer 11

i. Extensions of endothelial cells that reach through the internal elastic lamina to connect to VSMCs
ii. Gap junctions made of connexons can connect the two in myoendothelial junctions

Question 12

What are tight junction proteins?

Answer 12

1. Claudins
2. Occludins
3. Junctional adhesion molecules
   a. ZOs
   b. Anchors to the actin cytoskeleton

Question 13

Does hypertension cause BBB breakdown?

Answer 13

1. Hypertension can cause BBB breakdown but also the reverse is true

Question 14

Describe the effects of AngII on the BBB

Answer 14

ii. Hypertension->RAAS system dysregulated
iii. BBB protects the brain from high levels of AngII
iv. AngII can increase the number of leukocytes and platelets that adhere to the vascular wall
v. Hypertension, artery remodeling, and BBB permeability
vi. MMPs are secreted during remodeling, can increase BBB permeability
vii. Blood from hypertensive people- greater ROS content
g. Endothelial cells and hemostasis

Question 15

What are collaterals?

Answer 15

the collateral circ in the brain is a vascular network that allows for maintenance of blood flow once one conduit fails

Question 16

What are the secondary collaterals that are responsible for the redistribution of flow when there is an occlusion distal to the circle of Willis?

Answer 16

the pial network of leptomeningeal vessels

Question 17

What is the myogenic response?

Answer 17

an intrinsic property of smooth muscle to respond to changes in mechanical load or intravascular pressure

Question 18

What is the Bayliss effect

Answer 18

smooth muscles in large arteries and arterioles constrict in response to increased pressure and dilate in response to low pressure

Question 19

How does increased pressure cause vasoconstriction?

Answer 19

increased pressure leads to calcium influx via voltage-gated calcium channels
the rise in intracellular calcium increases MLC phos which leads to vasoconstriction

Question 20

What is one major negative feedback mechanism that limits myogenic vasoconstriction?

Answer 20

calcium-activated potassium channels are activated in response to calcium sparks
their activation leads to hyperpolarization of the cell

Question 21

What is EDHF?

Answer 21

endothelium-derived hyperpolarizing factor

hyperpolarizes the endothelial cell
the hyperpolarization is then transferred to the adjacent muscle cell
This might occur through myoendothelial junctions

Question 22

are parenchymal arterioles in close association with astrocytes?

Answer 22

yes

Question 23

are pial arteries and arterioles in close association with astrocytes?

Answer 23

no

Question 24

What happens to ERalpha localization within the hippocampus with aging?

Answer 24

increase in the dentate gyrus
increase in CA3
Decrease in CA1
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4024050/

Question 25

Does ERalpha increase in sensitivity to E2 with age or decrease?
ER beta?

Answer 25

ERalpha decreases in sensitivity while ER beta remains sensitive
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4024050/

Question 26

What does ovx do to glut receptors?

Answer 26

decrease in expression in the brain
E2 prevents the decline in expression
reproductive aging decreases brain glucose utilization

Question 27

Describe the synergistic relationship between estrogen receptors and the brain insulin growth factor receptor?

Answer 27

can form a macromolecule which can lead to Akt signaling
-> downstream increase in glucose uptake through GLUT4 upregulation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4024050/pdf/nihms-580925.pdf

Question 28

What is another name for pial collaterals

Answer 28

Leptomeningeal anastomoses

Question 29

Why are Leptomeningeal anastomoses important for stroke outcomes

Answer 29

These vessels redirect blood flow during an occlusion

Question 30

What is the effect of angiotensin II on cerebral blood flow?

Answer 30

Angiotensin II increases blood pressure by stimulating the Gq protein in vascular smooth muscle cells (which in turn activates an IP3-dependent mechanism leading to a rise in intracellular calcium levels and ultimately causing contraction).