Platelets are disklike anuclear cells that originate from megakaryocytes in the bone marrow, which shed their cytoplasm into thrombocyte size fragments afterward following a pattern of differentiation and maturation. The main hormone that controls megakorocyte development is thrombopoietin.
The life span of a thrombocyte in the circulation is 7-10 days. Circulating platelets in a resting state are discoid in shape and approximately 0.3-0.5µm in size. The expression platelet count in a healthy individual is 140-400x109/l.
Platelets have an important role in blood coagulation. When a watercraft is injured platelets immediately form a adulteress at the site of injury; this is called primary haemostasis. Secondary hemostasis occurs simultaneously:
Structure of blood platelets
Platelets have a exceedingly specialised body structure:
Figure 1 Shows the generalised structure of a platelet and organisation of the features to be discussed
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Platelet membrane
The platelet membrane is vital to platelet function for 2 reasons:
1. It contains a number of glycoprotein receptors through which platelets react with aggregating agents, inhibitors, coagulation instruments and consequently the vessel wall and each other. Some of the important glycoproteins include GP1a and GP1b.
GP1a binds to collagen and GP1b binds to von Willebrands factor
2. It too contains phospholipids, which act as a surface for interaction with ad hoc components of coagulation biochemistry, such as factor II and factor X
The surface connected open canalicular sytem (SCOCS) is a net income of take throughout the interior of the platelet formed from the invaginations of the membrane. These channels increase the surface area of platelet exposed to plasma. This provides a route for molecules to reach deep within the platelet cytoplasm. They withal provide a route for extrusion of substances out of the platelet once it has been activated.
The dense tubular system (DTS) is a...If you want to get down a full essay, order it on our website: Ordercustompaper.com
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