Describe megakaryocyte development and the role of endomitosis ...

[pragya sharda]

Describe megakaryocyte development and the role of endomitosis and thrombopoietin in this process.
 
  What will be an ideal response?

Question 2

Which of the following best describes the role of platelet factor 4?
 
  a. Stimulates platelet aggregation
  b. Contributes to fibrin formation
  c. Neutralizes heparin
  d. Acts as a mitogenic factor

[medine]

Answer to Question 1

Answer: Platelets develop from megakaryocytes. Megakaryocyte maturation is produced through endomitosis, which is different from mitosis because telophase is missing. As a result, nuclear duplication occurs without nuclear or cytoplasmic division. The resulting maturing cells are larger than in the previous stage. MK1 is smaller than MK2, which is smaller than MK3, which is smaller than MK4. The stages are very large (can reach up to 150 mcM), and can be easily spotted under low power when examining bone marrow specimens. These platelets respond to changes in thrombopoietin. Thrombopoietin interacts with c-MPL receptor on the megakaryocytes to induce thrombopoiesis and speed up the maturation time of the megakaryocyte. Mature platelets bud off the megakaryocyte and enter the circulation.

Answer to Question 2

Correct Answer: C

[pragya sharda]

Excellent

[atrochim]

Gracias!