Thrombocyte

Question 1

What precursors indicate that a stem cell has differentiated into the platelet lineage?

Answer 1

Megakaryoblasts, which become megakaryocytes that form platelets

Question 2

Life span

Answer 2

8–10 days

Question 3

Contains ____ granules (ADP, Ca2+) and ____ granules (vWF, fibrinogen, fibronectin)

Answer 3

Dense; α

Question 4

vWF receptor

Answer 4

GpIb

Question 5

Fibrinogen receptor

Answer 5

GpIIb/IIIa

Question 6

How do mature platelets form from large megakaryocyte precursors?

Answer 6

Small portions of cytoplasm fragment off of megakaryocytes

Question 7

What is the role of platelets immediately following an injury such as a laceration?

Answer 7

Primary hemostasis; for example, they help prevent leakage of red blood cells from damaged vessels

Question 8

What two types of granules do platelets contain?

Answer 8

Dense granules and alpha granules

Question 9

What are the contents of the dense granules of platelets?

Answer 9

Adenosine diphosphate, calcium

Question 10

What are the contents of the granules of platelets?

Answer 10

von Willebrand’s factor, fibrinogen

Question 11

Where in the body would you typically find the most platelets at any one time?

Answer 11

Approximately one third of the platelet pool is stored in the spleen