Platelets

Question 1

What is the primary shape of platelets?

Answer 1

Disc-shaped.

Question 2

What is the average diameter of a human platelet?

Answer 2

2 to 3 micrometers.

Question 3

True or False: Platelets are complete cells.

Answer 3

False.

Question 4

What type of cell do platelets originate from?

Answer 4

Megakaryocytes.

Question 5

Fill in the blank: Platelets are essential for __________.

Answer 5

Hemostasis.

Question 6

What is the main function of platelets?

Answer 6

To prevent bleeding by forming clots.

Question 7

How do platelets aggregate?

Answer 7

By adhering to damaged blood vessels and to each other.

Question 8

What is the lifespan of a platelet in circulation?

Answer 8

Approximately 7 to 10 days.

Question 9

True or False: Megakaryocytes are found in the bone marrow.

Answer 9

True.

Question 10

What is the size range of megakaryocytes?

Answer 10

20 to 100 micrometers.

Question 11

What is the process called by which platelets are formed?

Answer 11

Thrombopoiesis.

Question 12

Which hormone regulates the production of platelets?

Answer 12

Thrombopoietin.

Question 13

What structural feature allows platelets to change shape?

Answer 13

The cytoskeleton.

Question 14

What do platelets release during aggregation?

Answer 14

Chemicals such as ADP and thromboxane A2.

Question 15

True or False: Platelets contain organelles like mitochondria.

Answer 15

True.

Question 16

What is the primary component of the platelet membrane?

Answer 16

Phospholipids.

Question 17

Fill in the blank: Platelet aggregation is primarily mediated by __________.

Answer 17

Fibrinogen.

Question 18

What is the surface receptor involved in platelet activation?

Answer 18

Glycoprotein IIb/IIIa.

Question 19

How do platelets adhere to the damaged endothelium?

Answer 19

Through von Willebrand factor.

Question 20

What is the role of calcium ions in platelet function?

Answer 20

They are essential for activation and aggregation.

Question 21

True or False: Platelets can also play a role in inflammation.

Answer 21

True.

Question 22

What happens to platelets when they become activated?

Answer 22

They change shape and become sticky.

Question 23

Which part of a megakaryocyte is shed to form platelets?

Answer 23

Proplatelets.

Question 24

Fill in the blank: The process of platelet aggregation can lead to the formation of a __________.

Answer 24

Platelet plug.

Question 25

What is the function of alpha granules in platelets?

Answer 25

They store proteins and growth factors.

Question 26

What is the primary function of dense granules in platelets?

Answer 26

They store ADP, calcium, and serotonin.

Question 27

What is the significance of platelet size in their function?

Answer 27

Larger platelets may be more reactive.

Question 28

True or False: Platelets are involved in wound healing.

Answer 28

True.

Question 29

Which pathway activates platelets during coagulation?

Answer 29

The intrinsic and extrinsic pathways.

Question 30

What is the term for the process of programmed cell death in platelets?

Answer 30

Apoptosis.

Question 31

What is the role of phosphatidylserine in platelets?

Answer 31

It promotes coagulation by providing a surface for clotting factors.

Question 32

Fill in the blank: The interaction between platelets and the vascular wall is called __________.

Answer 32

Adhesion.

Question 33

What is the role of platelet-derived growth factor (PDGF)?

Answer 33

To promote healing and tissue regeneration.

Question 34

How do aspirin and other antiplatelet drugs affect platelet function?

Answer 34

They inhibit platelet aggregation.

Question 35

True or False: Platelets can synthesize new proteins.

Answer 35

False.

Question 36

What triggers the release of granules from activated platelets?

Answer 36

Calcium influx.

Question 37

What is the role of thrombin in platelet activation?

Answer 37

It activates platelets and promotes aggregation.

Question 38

What is the effect of shear stress on platelets?

Answer 38

It can enhance platelet activation and aggregation.

Question 39

Fill in the blank: Platelet function is essential for maintaining __________.

Answer 39

Hemostasis.

Question 40

What is the significance of the platelet activation phase?

Answer 40

It is crucial for forming a stable clot.

Question 41

What is the term for the formation of a stable clot involving platelets and fibrin?

Answer 41

Coagulation.

Question 42

What is the role of the cytoskeleton in platelets?

Answer 42

It maintains shape and facilitates shape change during activation.

Question 43

How do platelets interact with leukocytes?

Answer 43

They can modulate inflammation and immune responses.