Hematopoiesis Flashcards Preview

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Flashcards in Hematopoiesis Deck (20):
1

1st Trimester

- Primordial erythroblasts in yolk sac

2

2nd Trimester

- Hepato-Spleno-Thymic Phase
- Produce precursor granulocytes and megakaryocytes, and also definitive erythroblasts
- Liver and Spleen

3

3rd Trimester

- Medullo-Lymphatic Phase
- bone marrow and lymph nodes produce all cell types

4

2 Pathways for Hematopoiesis

1) Myeloid
2) Lymphoid

5

Myeloid Stem Cells

- multipotential lineages, capable of self renewal
- erythrocytes
-megakaryocytes
- granulocytes
- Monocytes

6

Lymphoid Stem Cells

- multipotential lineages, capable of self renewal
- Lymphocytes (T&B)

7

General Trends During Myeloid Hematopoiesis

- Reduction of potentiality- As cells progressively differentiate, they can not go back the opposite way of the pathway
- increase in mitotic activity
- Leukemias/ Lymphomas- intermediate froms are not progresing to the final form of blood, functional deficit of final product

8

Red Marrow

- Hematogenous (young)
- hematopoeitic tissue is very active

9

Yellow Marrow

- Older
- replacement with adipose cells (fat cells)

10

Vasculature of Bone Marrow

- Occurs after birth
- Blood vessels msut penetrate into bone marrow
- Brings in oxygen and nutrients and also a pathway for mature cells

11

Stromal Cells

- Support cell
- Provides environment that induces hematopoiesis

12

Erthropoietin

- Secreted into the blood by the kidney when oxygen levels are low
- stimulates the proliferation and differentiation of erythroid progenitors into reticulocytes
- Reticulocytes differentiate into erythrocytes
- Increases oxygen to tissues

13

Erythropoiesis

- Proerythroblast differentiates into Basophilic Erythroblast
- Then that differentiates inot polychromatophilic erythroblasts (two colors) where the nucleus is starting to condense
- further condensation until dark nucleus with little cytoplasm- Normoblast
- Gets rid of nucleus to become polychromatophilic erythrocyte (reticulocyte)
- Then it becomes a mature red blood cell

14

Hemoglobin and RNA during Erythropoiesis

- As erythropoiesis progresses, Hemoglobin increases while RNA content and mitochondria decrease

15

Reticulocytes

- No nucleus but have some RNA left
- Normally, about 1% of the RBC's in blood are reticulocytes

16

Granulopoiesis (Neutrophil)

- promyelocyte- has non specific granules
- Differentiates into Myelocyte, which has specific granules
- Specifically Neutrophillic myelocyte
- Differentiates into Metamyelocyte, where lobulation begins, looks like a kidney bean
- Differentiates into band cell- looks like a horseshoe
- Then differentiates into neutrophil

17

Excess Band Neutrophil Accumulation

- indicates bacterial infection

18

Lymphoma

- neoplasm of lymphoid system
- Hodgkin's disease, characterized by the presence of giant Reed-Sternberg (RS) cells- 5 subtypes
- Non Hodgkin's Lymphomas- 12 B cell types, 12 T cell types

19

Leukemias

- neoplasm of leukocytes and precursors
- acute- immature cells- progresses rapidly
- chronic- more mature cells- less aggressive

20

Myelogenous Leukemia

- Myeloid Lineage
- primarily involves bone marrow
- classified based on type of precursor cell (erythrocytic, granulocytic, monocytic)
- acute and chronic
- tumor cells replace normal hematopoietic tissue