Platelet Cytoskeleton Components

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Questions and Answers

What is the normal range for platelets in the blood?

150-400x10^9/L

What is the main source of energy for platelets?

glucose

What is the average lifespan of platelets?

7-10 days (Rodak: 8-9 days)

What is the main stimulus for the production of platelets?

Thrombopoietin Signup and view all the answers

What is the principal site for ATP synthesis in platelets?

Mitochondrion Signup and view all the answers

Which organelle in platelets is responsible for storing small molecules that are endocytosed?

Dense body Signup and view all the answers

What component of platelet protein constitutes 20% to 30% of the platelet cytoplasm?

Actin Signup and view all the answers

Which organelle in platelets is responsible for digesting materials that are endocytosed by the platelets?

Lysosome Signup and view all the answers

What is the role of FOG-1 and GATA-1 in megakaryocyte endomitosis?

Slows the transition from mitosis to endomitosis by preventing actin and myosin cytoskeleton and cytokinesis Signup and view all the answers

What is the significance of 128N in megakaryocyte biology?

Indicates a hematologic disease Signup and view all the answers

Describe the characteristics of a promegakaryocyte (MK-II) in the terminal differentiation phase.

Indention begins, abundant cytoplasm with few fine azurophilic granules, more developed demarcation system Signup and view all the answers

What are the key features of a megakaryocyte (MK-III) in the terminal differentiation phase?

Intense indentation and lobulation, lobulated nucleus, basophilic chromatin pattern, visible and defined demarcation system, azurophilic and granular, platelet shedding, alpha and dense granules Signup and view all the answers

What is the function of the Open canalicular system in platelets?

Enhances platelet interaction with its environment. Route for endocytosis and secretion of alpha granules upon activation. Signup and view all the answers

What is the role of Von Willebrand Factor (VWF) in platelet adhesion?

VWF is stored in Weibel palade bodies and serves as a substrate for platelet adhesion. Signup and view all the answers

How is platelet and VWF regulated?

Platelet and VWF is regulated by ADAMTS-13 (VWF cleaving protease). Signup and view all the answers

What happens at high shear rates in platelets?

At high shear rates, platelets bind to collagen via GP VI, triggering an internal platelet activation pathway. Signup and view all the answers

What is the consequence of the 'outside-in-reaction' in platelets?

The release of ADP and TXA2, which are potent vasoconstrictors. Signup and view all the answers

What is the result of the 'inside-out' reaction in platelets?

It causes an increase in the affinity of integrin a2B1 for collagen, platelet shape change, and activation of neighboring platelets. Signup and view all the answers