Resources: local and reflex control of blood flow

Question 1

Which one is an important source of substances that cause contraction or relaxation of vascular smooth muscle?

Answer 1

The endothelium

Question 2

The role of prostacyclin, or prostaglandin I2 (PGI2)

Answer 2

PGI2 can relax vascular smooth muscle via an increase in cyclic adenosine monophosphate (cAMP)

Question 3

How is PGI2 formed?

Answer 3

in the endothelium from arachidonic acid, and the process is catalyzed by PGI2 synthase.

Question 4

The primary function of PGI2 is ___

Answer 4

1) To inhibit platelet adherence to the endothelium and platelet aggregation and thus prevent intravascular clot formation.
2) causes relaxation of vascular smooth muscle.