Vasoconstriction and Vasodilation

Question 1

When Ca goes up, what happens? endothelial cell. But what happens after?

Answer 1

increase in contractility
Ca increase, increases NO, and citrulline, diffuses into the vascular smooth muscle and cGMP. (PKG/PKA)

Question 2

Acetylcholine, bradykinin, increased shear forces, and stress from hypertension will _____

Answer 2

increase endothelial calcium concentration

Question 3

Nitric oxide, cGMP, and arginine are all associated with what?

Answer 3

vascular smooth muscle relaxation and vasodilation

Question 4

What does calcium bind to in the contraction mechanism?

Answer 4

Ca binds to tropnon-c, so actin and myosin get together and make the cross bridge

Question 5

How do we go from contraction to relaxation? what is the name of the channel?

Answer 5

SERCA channel, sequesters intracellular calcium into SR via ATP relaxation

Question 6

How does contraction differ in myocytes, vs smooth muscle vs skeletal muscle?

Answer 6

everything gets depolarized
Myocytes: tropinin, RyR, SERCA
Smooth Muscle: calcium binds calmodulin induces a phosphorylation change in myosin light chain kinase, once it dephosphorylates relaxes again.
Skeletal muscle: stimulated by AcH

Question 7

How does the excitation contraction work in smooth muscle cells?

Answer 7

L- type calcium channel opens up.
GPCR- Gq: NE–> DAG/IPR, IP3 goes to the Sarcoplasmic Reticulum and makes the Ca go out. **Calcium binds to Calmodulin– stimulate myosin light chain kinase->help cross bridge formation and contractility.

Question 8

What is the mechanism of excitation and contraction in skeletal muscle?

Answer 8

stimulated by AcH, neuromuscular junction. there are no calcium channels*** L type Calcium channels are not mechanically coupled with ryanodine receptors

Question 9

Which receptor is associated with alpha 1?

Answer 9

Gq

Question 10

Where are the Gq receptors found and what it’s the effect?

Answer 10

found on arterioles (increases afterload) and on veins (increases preload)

Increases the Phospholipase C, tells calcium to come out, and cuts PIP2, and stimulates IP3–which stimulates calcium release from the SR and DAG (PKC)

Question 11

Adenosine is associated with what?

Answer 11

vasodilation

Question 11

What type of medications to avoid in inferior wall MI?

Answer 11

Venous dilating medications (NO, hydralazine, minoxidil, nitroprusside)