PLATELETS

Question 1

How are platelets formed?

Answer 1

Platelets are formed in the bone marrow by fragmentation of megakaryocytes.

Question 2

What role do platelets play in blood coagulation?

Answer 2

Platelets trigger and control blood coagulation by participating in the formation of blood clots

Question 3

What happens when platelets adhere to damaged surfaces of blood vessels?

Answer 3

Platelets rapidly adhere to damaged surfaces of blood vessels and secrete proteins and small molecules that trigger thrombosis or clot formation.

Question 4

what is the size of platelets

Answer 4

2-4 micrometer

Question 5

how do platelets maintain blood vessel integrity

Answer 5

by instigating vessel wall repair.

Question 6

how do platelets accomplish their clot formation process

Answer 6

Platelets rapidly adhere to damaged surfaces of blood vessels, and secrete proteins and small molecules

Question 7

what are the effects of uncontrolled platelet

Uncontrolled platelets can refer to two different conditions:

Thrombocytosis (High Platelet Count) and Platelet Function Disorders:
Platelet function disorders occur when platelets don’t work as they should.

Answer 7

Deep vein thrombosis
Pulmonary emboli
Acute myocardial infarction(heart attacks), Celebrovascular accidents (strokes)
Peripheral artery disease
Repeated spontaneous abortions (miscarriage).

Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in the body, usually in the legs. Pulmonary embolism (PE) occurs when one of the arteries in the lungs becomes blocked by a blood clot. Peripheral artery disease (PAD), also known as peripheral arterial disease, is a common vascular disorder characterized by the abnormal narrowing of arteries

Question 8

What is the mean platelet volume (MPV) and how is it generated?

Answer 8

indicating the average volume of platelets in blood

Question 9

What does an elevated MPV value indicate?

Answer 9

An elevated MPV value, resulting from the presence of predominantly larger platelets, can sometimes signal a regenerative bone marrow response to increased platelet consumption.

Question 10

Can you explain what Essential Thrombocythaemia (ET) is

Answer 10

ET is a rare malignant condition characterized by extremely high platelet counts and uncontrolled platelet production, making it a life-threatening haematological disorder.

Question 10

What does thrombocytosis refer to and what does it indicate

Answer 10

Thrombocytosis refers to elevated platelet counts in the blood, which can be a signal of inflammation or trauma but generally carries small intrinsic significance

Question 11

What is thrombocytopenia?

Answer 11

Thrombocytopenia is a condition characterized by a low platelet count, which can be a common consequence of drug treatment and may be life-threatening

Question 12

Why does thrombocytopenia occur?

Answer 12

Thrombocytopenia occurs due to a decreased number of platelets in the blood. These platelets play a crucial role in maintaining normal blood vessel function and repair

Question 13

What symptoms are associated with thrombocytopenia?

Answer 13

bruising
uncontrolled hemorrhage

Question 14

What role do thrombocytes (platelets) play in blood vessel maintenance

Answer 14

Thrombocytes are responsible for maintaining and repairing blood vessels. They help form blood clots to prevent excessive bleeding and promote healing

Question 15

What conditions might lead to thrombocytopenia

Answer 15

Thrombocytopenia can occur in response to drug treatments, certain diseases, or other medical conditions. It’s essential to identify the underlying cause for appropriate management

Question 16

What is the normal range for platelet counts in circulation?

Answer 16

Platelets typically circulate in amounts of 150 to 400 x 10⁹/L.

Question 17

How do mean platelet counts differ between women and men?

Answer 17

Mean platelet counts are slightly higher in women compared to men

Question 18

What is the distribution pattern of platelets on a Wright-stained wedge preparation blood film

Answer 18

On a Wright-stained wedge preparation blood film, platelets are distributed throughout the red blood cell monolayer at a rate of 7 to 21 per 100x field.

Question 19

What is the average diameter of platelets

Answer 19

2.5µm

Question 20

What does the mean platelet volume (MPV) correspond to

Answer 20

The mean platelet volume (MPV) corresponds to a range of 8 to 10 fL

Question 21

How would you describe the internal structure of platelets under a light microscope?

Answer 21

The internal structure of platelets is complex and granular

Question 22

What are platelets, and from which bone marrow cells do they arise?

Answer 22

Platelets are small, disc-shaped blood cells involved in clotting. They arise from megakaryocytes, which are unique bone marrow cells

Question 23

Describe the process of megakaryocyte maturation. What makes it mysterious?

Answer 23

Megakaryocyte maturation involves a form of mitosis called endomitosis. Unlike typical mitosis, endomitosis lacks telophase and cytokinesis. This mysterious process results in megakaryocytes with multiple sets of chromosomes.

Question 24

What is endomitosis, and how does it differ from typical mitosis?

Answer 24

Endomitosis is a cell division process where the cell replicates its DNA without undergoing full cell division. Unlike regular mitosis, endomitosis skips the final stages of cell division, resulting in cells with multiple nuclei.

Question 25

Explain the role of spindle fiber orientation during endomitosis

Answer 25

During endomitosis, the loss of spindle fiber orientation at the point of telophase prevents chromosomes from proceeding to polar bodies. Instead, they duplicate in place within the cell.

Question 26

Why do chromosomes duplicate in place during endomitosis instead of proceeding to polar bodies?

Answer 26

The altered spindle fiber orientation disrupts the normal movement of chromosomes, causing them to remain in place. This unique adaptation ensures that cytokinesis (cell separation) is arrested.

Question 27

What makes this cell cycle adaptation in megakaryocytes unique?

Answer 27

The lack of cytokinesis during endomitosis is specific to megakaryocytes and is not observed in other normal human cells. It allows these cells to produce platelets efficiently.

Question 28

What is endomitosis, and how does it differ from regular cell division?

Answer 28

Endomitosis is a cell division process where DNA replication occurs without subsequent cell division. Unlike typical mitosis, endomitosis lacks cytokinesis, resulting in cells with multiple sets of chromosomes.

Question 29

what does “polyploid” mean?

Answer 29

Polyploid refers to possessing multiple copies of chromosomes within a single cell.

Question 30

What ploidy levels are achieved during endomitosis

Answer 30

Endomitosis leads to ploidy levels of 8N, 16N, or 32N

Question 31

Why is reaching 128N ploidy unusual in megakaryocytes?

Answer 31

Megakaryocytes, which replicate their nuclei up to 128N, exhibit unusually high ploidy. Such levels may indicate hematologic diseases.

Question 32

How do megakaryocytes utilize their abundant DNA?

Answer 32

Megakaryocytes use their copious DNA to synthesize abundant cytoplasm, which eventually differentiates into platelets

Question 33

How many platelets can a single megakaryocyte shed?

Answer 33

A single megakaryocyte can shed 2000 to 4000 platelets.

Question 34

What is the daily platelet production by megakaryocytes in an average-sized healthy human?

Answer 34

An average-sized healthy human has approximately 10⁸ megakaryocytes, producing 101¹¹ platelets per day.