NURS 5315: Advanced Pathophysiology Hematologic Module 4 Questions with 100% Correct Answers What is the peripheral zone of platele

NURS 5315: Advanced Pathophysiology Hematologic Module 4 Questions with 100% Correct Answers What is the peripheral zone of platelet? Outermost layer. Made of phospholipids. Contains many receptors responsible for platelet adhesion and aggregation What is the sol-gel of the platelet It is the outermost layer made of possible if it contains many receptors responsible for platelet adhesion and aggregation What is the organelle zone of platelets Innermost layer contains calcium dense granules and alpha granules What are the four phases of platelet plug formation? Activation, adherence, aggregation, and secretion What is the first step or phase of platelet plug formation and explain Activation is the first step. In physiological states. Platelets circulate without adhering to the intact endothelium. An injury to the endothelium exposes thev WF, fibronectin, collagen and from thrombospondin.. Collagen is a potent activator and when the sub endothelial collagen is exposed by an injury. The platelets become charged AKA activated. Platelets and become aware of the injury and undergo a shape change that increases their ability to adhere to the site of injury. The second step in platelet plug formation is Adherence is a process by which platelets attached to the injured endothelium. Adherence begins with the vWF. Circulating vWF binds to the exposed subendothelial collagen and to the GP Ib/IX/V receptors on circulating platelets. Collagen then binds with the GP VI receptor. The binding of collagen with the GP VI receptor results in the activation of the GPIIb/IIIa and GPIa/IIa receptors. vWF then binds with the GPIIb/IIIa receptors and collagen further binds with the GPIa/IIa receptors. This collective binding anchors the platelets in place The third step in platelet plaque formation is Aggregation- is the process by which platelets bind to one other. There are multiple GPIIb/IIIa receptors on one platelet and when activated (as described above) they have a greater affinity for fibrinogen. Fibrinogen is able to bind to two GPIIb/IIIa receptors simultaneously and thereby bind platelets together The fourth step in platelet plug formation is Secretion- during this phase the platelet granules release their contents. a. ADP- enhances adhesion, activates platelets and recruits platelets b. Serotonin recruits platelets. c. Fibronectin and thrombospondin are proteins which stabilize platelets that are adhered to the site of injury. d. Thromboxane A2- is a product of the arachidonic acid pathway but is stored inside the platelet too. It causes vasoconstriction and enhances platelet aggregation. e. Growth factors promote tissue repair however they have a role in the development of atherosclerosis.