Megakaryocytes

Definition

Megakaryocytes are large, polyploid cells found in the bone marrow that are responsible for the production of platelets, which are essential for blood clotting and wound healing.

5 Must Know Facts For Your Next Test

1. Megakaryocytes are the largest cells in the bone marrow, with a diameter of up to 100 micrometers.
2. They undergo endomitosis, a process of nuclear division without cell division, resulting in their polyploid nature.
3. Megakaryocytes produce platelets through a process called fragmentation, where they extend long, branching cytoplasmic processes called proplatelets that break off to form individual platelets.
4. The development and maturation of megakaryocytes are regulated by the cytokine thrombopoietin, which is produced primarily by the liver and kidneys.
5. Abnormalities in megakaryocyte production or function can lead to various platelet disorders, such as thrombocytopenia (low platelet count) or thrombocytosis (high platelet count).

Review Questions

• Describe the role of megakaryocytes in the production of platelets.
  • Megakaryocytes are responsible for the production of platelets, which are essential for blood clotting and wound healing. Through a process called fragmentation, megakaryocytes extend long, branching cytoplasmic processes called proplatelets that break off to form individual platelets. This process is regulated by the cytokine thrombopoietin, which stimulates the production and maturation of megakaryocytes, leading to increased platelet production.
• Explain the significance of the polyploid nature of megakaryocytes.
  • Megakaryocytes are polyploid cells, meaning they contain more than the normal diploid number of chromosomes. This polyploid characteristic enables them to produce large quantities of platelets. During the process of endomitosis, megakaryocytes undergo nuclear division without cell division, resulting in their increased DNA content. This allows them to generate the necessary cellular machinery and resources to produce the vast number of platelets required for blood clotting and wound healing.
• Analyze the potential clinical implications of abnormalities in megakaryocyte production or function.
  • Disruptions in the normal production or function of megakaryocytes can lead to various platelet disorders. For example, a decrease in megakaryocyte production or maturation can result in thrombocytopenia, a condition characterized by a low platelet count, which can increase the risk of excessive bleeding and impaired wound healing. Conversely, an increase in megakaryocyte production or abnormal platelet release can lead to thrombocytosis, a high platelet count that may contribute to the formation of blood clots and increase the risk of cardiovascular events. Understanding the role of megakaryocytes in platelet homeostasis is crucial for the diagnosis and management of these platelet-related disorders.

Related terms

Platelets: Small, anucleate cell fragments derived from megakaryocytes that play a crucial role in blood clotting, wound healing, and immune function.

Thrombopoietin: A glycoprotein hormone produced primarily by the liver and kidneys that stimulates the production and maturation of megakaryocytes, leading to increased platelet production.

Polyploid: A cell that contains more than the normal diploid number of chromosomes, a characteristic of megakaryocytes that enables them to produce large quantities of platelets.