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Questions and Answers
What is the origin of platelets?
What is the origin of platelets?
What is the mechanism that leads to cessation of bleeding from a blood vessel?
What is the mechanism that leads to cessation of bleeding from a blood vessel?
What is the function of platelets in primary hemostasis?
What is the function of platelets in primary hemostasis?
What is the substance ultimately formed in the coagulation cascade?
What is the substance ultimately formed in the coagulation cascade?
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What are megakaryocytes descended from?
What are megakaryocytes descended from?
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Study Notes
Origin of Platelets
- Platelets originate from megakaryocytes, large bone marrow cells that undergo a process called thrombopoiesis.
- Megakaryocytes extend their cytoplasmic processes into the bloodstream, where fragments are released as platelets.
Mechanism of Cessation of Bleeding
- The cessation of bleeding involves vasoconstriction, the formation of a platelet plug, and the activation of the coagulation cascade.
- Platelets adhere to the exposed collagen at the site of injury, activating and releasing chemical signals that recruit more platelets.
Function of Platelets in Primary Hemostasis
- Platelets are crucial for primary hemostasis by aggregating at the injury site to form a temporary plug.
- They release various substances, including ADP and thromboxane A2, which promote further platelet activation and aggregation.
Substance Formed in the Coagulation Cascade
- The ultimate substance formed in the coagulation cascade is fibrin, which stabilizes the platelet plug and forms a solid blood clot.
- Fibrinogen, a plasma protein, is converted to fibrin through the action of thrombin during the cascade.
Origin of Megakaryocytes
- Megakaryocytes are derived from hematopoietic stem cells in the bone marrow.
- They differentiate and mature through various stages and are stimulated by thrombopoietin, a hormone that regulates platelet production.
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Description
Test your knowledge of platelets and megakaryocytes with this quiz! Learn about the unique characteristics and functions of these cell fragments.
