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Megakaryocytopoiesis and Thrombopoiesis
hematology
31
Health Care
Undergraduate 4
06/06/2009

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Cards

Term
Are nucleoli usually seen in the mature megakaryocyte nucleus?
Definition
No. Rarely.
Term
What multipotential stem cell does the megakaryocyte originate from?
Definition
CFU-GEMM
Term
What hormone stimulates the production of CFU-Meg?
Definition
Thrombopoietin.
Term
What is the difference between stress platelets and regular platelets?
Definition
Stress platelets are larger in size because of shorter maturation and release time; produced in response to thrombocytopenia.
Term
What is endomitosis?
Definition
DNA replication without cytoplasmic divisions. Results in one multilobed nucleus.
Term
A giant polyploid cell is produced by what process?
Definition
endomitosis.
Term
The ploidy of the megakaryocyte correlates with what 2 things?
Definition
Size of megakaryocyte and number of platelets produced.
Term
At what ploidy does a megakaryocyte become morphologically recognizable as a megakaryocyte?
Definition
8N.
Term
Stages of megakaryocyte maturation-
Definition
Megakaryoblast, Promegakaryocyte, Granular megakaryocyte, Mature megakaryocyte.
Term
What is the N:C ratio of the megakaryoblast?
Definition
10:1
Term
How many nucleoli are present in the nucleus of the megakaryoblast?
Definition
2-6 nucleoli.
Term
What shape is the megakaryoblast nucleus?
Definition
Round to oval.
Term
What megakaryocyte precursor has blunt cytoplasmic projections or blebs at periphery?
Definition
Megakaryoblast
Term
What stage is the earliest morphologically recognizable megakaryocyte?
Definition
Promegakaryocyte.
Term
What is the shape of the promegakaryocyte nucleus?
Definition
irregular and lobulated
Term
How many nucleoli are usually present in the promegakaryocyte?
Definition
0-2
Term
What is the N:C ratio of the promegakaryocyte?
Definition
4:1 to 7:1
Term
What is the ploidy of the promegakaryocyte?
Definition
8N to 32N
Term
What is the nucleus like in the granular megakaryocyte?
Definition
condensed multilobulated nucleus- 8N- 32N
Term
Can endomitosis occur in the granular megakaryocyte?
Definition
Yes.
Term
What is the N:C ratio in the mature megakaryocyte?
Definition
1:1 or less.
Term
What is the ploidy of the majority of the megakaryocytes in the bone marrow?
Definition
16N
Term
Is it possible to determine ploidy of a megakaryocyte by looking at it?
Definition
No.
Term
The average megakaryocyte releases how many platelets?
Definition
2000 to 4000
Term
After being released from the bone marrow, where do the baby platelets go?
Definition
to the spleen.
Term
How long do platelets stay in the splenic platelet pool before being distributed throughout the body?
Definition
2-4 days.
Term
How long do platelets survive?
Definition
5-12 days.
Term
What portion of the platelets is in the spleen at any given time?
Definition
about 1/3
Term
What 3 kinds of granules are in the platelet?
Definition
alpha, lysosomes, dense bodies.
Term
What are the most numerous granules in the platelet?
Definition
alpha granules
Term
Contents of dense bodies?
Definition
ADP, ATP, Ca2+, serotonin
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