Structure and Action Flashcards
(10 cards)
Structure and action
The structural differences between prostaglandins account for their different biological activities. A given prostaglandin may have different and even opposite effects in different tissues in some cases. The ability of the same prostaglandin to stimulate a reaction in one tissue and inhibit the same reaction in another tissue is determined by the type of receptor to which the prostaglandin binds. They act as autocrine or paracrine factors with their target cells present in the immediate vicinity of the site of their secretion. Prostaglandins differ from endocrine hormones in that they are not produced at a specific site but in many places throughout the human body.
The ability of the same prostaglandin to stimulate a reaction in one tissue and inhibit the same reaction in another tissue is determined by
by the type of receptor to which the prostaglandin binds
They act as ——- or ——– factors with their target cells present in the ———- vicinity of the site of their secretion.
They act as autocrine or paracrine factors with their target cells present in the immediate vicinity of the site of their secretion.
How do PGs differ from hormones?
they are not produced at a specific site but in many places throughout the human body.
Prostaglandins are powerful, _______-acting ______ that also inhibit the ______ of platelets. Through their role in vasodilation, prostaglandins are also involved in _______ They are synthesized in the _____ of blood vessels and serve the physiological function of preventing needless clot formation, as well as regulating the _______ of smooth muscle tissue.
Prostaglandins are powerful, locally-acting vasodilators that also inhibit the aggregation of blood platelets. Through their role in vasodilation, prostaglandins are also involved in inflammation. They are synthesized in the walls of blood vessels and serve the physiological function of preventing needless clot formation, as well as regulating the contraction of smooth muscle tissue.
Conversely, _______ (produced by platelets) are _____ and facilitate platelet ______. Their name comes from their role in clot formation (_________).
Conversely, thromboxanes (produced by platelets) are vasoconstrictors and facilitate platelet aggregation. Their name comes from their role in clot formation (thrombosis).
Naming of prostaglandins
Specific prostaglandins are named with a letter indicating the type of ring structure, followed by a number indicating the number of double bonds in the hydrocarbon structure. For example, prostaglandin E1 has the abbreviation PGE1 and prostaglandin I2 has the abbreviation PGI2.
Structure of prostacyclin - I2
Prostaglandins were believed to be part of ————— secretions , and eventually were discovered to be produced by the ————-vesicles.
Prostaglandins were believed to be part of the prostatic secretions, and eventually were discovered to be produced by the seminal vesicles.
In what parts of the blood vessel wall are PGs produced?
Prostaglandins are primarily synthesized by the endothelial cells of the blood vessel wall. These cells line the inner surface of blood vessels and are the main site of synthesis for prostaglandins, particularly PGI2 (prostacyclin). While other cells in the vessel wall, like vascular smooth muscle cells, also produce prostaglandins, endothelial cells are the primary source.
