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Flashcards in Bone Marrow Deck (16)
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0
Q

What is the first phase of hemopoiesis and when does it begin? Where does it occur?
Other stages?

A

mesoblastic phase, 2 weeks after fertilization; yolk sac
hepatosplenic phase, about 2nd month of gestation; spleen and liver
myeloid phase, end of 2nd trimester and continues throughout life; bone marrow

1
Q

Hemopoietic tissue consists of ___ and ___.

A

bone marrow (myeloid tissue), lymphoid tissue

2
Q

Hematopoietic stem cells differentiate from early embryonic stem cells (pluripotent cells) into two types of multipotential cells. What are they, and which blood cells do they ultimately differentiate into?

A

Lymphoid multipotential cells -> lymphoblasts -> B and T cells
Myeloid multipotential cells -> RBCs, megakaryocytes, the rest of the WBCs

3
Q

In which stage of hematopoietic cell differentiation do morphological characteristics develop? When do they lose their potentiality? When do they lose their self-renewing capacity?

A

Precursor cell (blast cell) stage for all three.

4
Q

In erythropoiesis, the mother cell is the ____, and the last two cell phases are ___.

A

Proerythroblast, reticulocyte, erythrocyte

5
Q

How can early basophilic myelocytes be distinguished from early eosinophilic myelocytes or promyelocytes?

A

The early stage basophils have dark blue granules.

6
Q

What are the stages of erythropoiesis and how can they be distinguished? When does mitosis stop occuring? When does Hb synthesis start?

A

Proerythroblast: large cell, loose chromatin, multiple visible nucleoli, basophilic (blue) cytoplasm
Basophilic erythroblast: (onset of Hb synth) more acidic RNA-rich cytoplasm (bluest of all hematopoietic cells), condensed nucleus, no visible nucleoli
Polychromatophilic erythroblast: cytoplasmic Hb and fewer polyribosomes creates eosinophilic and basophilic cytoplasm
-Mitosis stops-
Orthochromatophilic erythroblast: cytoplasm filled with Hb (same color as RBC cytoplasm), few polyribosomes, condensed eccentrically-located nucleus (getting ready for ejection)
Normoblast: late orthochromatophilic erythroblast
Reticulocyte: Anucleate, released to blood where maturation culminates

7
Q

At which stage of erythropoiesis is the nucleus extruded?

A

Orthochromatophilic erythroblast -> reticulocyte (sans nucleus)

8
Q

What are the stages of granulopoiesis? What are their morphological characteristics and when does mitosis stop?

A

Myeloblast: large round nucleus, dispersed chromatin, visible nucleoli
Promyelocyte: biggest cell, basophilic cytoplasm, azurophilic granules (lysosomes)
Myelocyte: coarse chromatin, cell-specific granules appear
-Mitosis stops-
Metamyelocyte: indented dense nucleus, granules increase in number
Band form: band/ribbon shaped nucleus (segmented), released to blood

9
Q

What are the stages of monopoiesis?

A

Monoblast: similar to myeloblast, large nucleus, dispersed chromatin
Promonocyte: large cell, basophilic cytoplasm, indented nucleus, lacy chromatin, visible nucleoli
-Mitosis stops-
Monocyte: horseshoe/kidney-shaped nucleus

10
Q

Lymphocyte progenitors initially come from ____ and migrate to the ____ where circulating lymphocytes originate.

A

bone marrow, thymus/peripheral lymphoid tissue

11
Q

What are the two progenitors of lymphopoiesis? Where are they found? What are their characteristics?

A

Lymphoblast: in bone marrow, large cell, can divide 2-3 times
Prolymphocyte: smaller cell, denser chromatin, lacks surface antigens that distinguish T and B cells (they migrate to lymphoid tissues where they mature into immunocompetent cells)

12
Q

What are the differences between chronic and acute leukemia?

A

Chronic: slow progression, proliferating cells are more differentiated (myelocytes, metamyelocytes, band cells)
“Chronic granulocytic leukemia”
Acute: rapid progression, proliferating cells are precursors (myeloblasts)
“Acute myeloblastic leukemia”

13
Q

Platelets are formed from ___?

A

megakaryocytes

14
Q

Thrombocytopenia is…

A

reduction in number of circulating platelets. Can cause petechia, purpura, ecchymoses

15
Q

How can a proerythroblast be distinguished from a myeloblast?

A

The cytoplasm of a proerythroblast is slightly more basophilic (bluer).