Hematopoiesis

Question 1

What is the monophyletic theory?

Answer 1

This is the theory that the hematopoietic stem cell can give rise to all the different progeny of the blood cells/formed elements of the main chart.

Question 2

When and where does hematopoiesis begin?

Answer 2

In the fetus during the first trimester and it begins in the umbilical vesicle (in hematopoietic islands).

Question 3

Where is the location of hematopoiesis after the 2nd trimester?

Answer 3

Liver (and some involvement of the spleen).

Question 4

What is the location of hematopoiesis during the seventh month of gestation?

Answer 4

Bone marrow

Question 5

What is the primary location of hematopoiesis during childhood?

Answer 5

Long bones

Question 6

What is the primary location of hematopoiesis during adulthood?

Answer 6

Vertebrae, sternum, and ribs

Question 7

What are sinusoids?

Answer 7

These are vascular units that consist of a endothelial cells lining and a discontinuous basement membrane (meaning that the basement membrane is open and porous). This is important because it allow the cells to be able to pass through the sinusoid so that they can get in the circulation

Question 8

What are the functions of adventitial cells?

Answer 8

They partially cover the boundary and provide support for developing blood cells. They produce reticular fibers for the reticular tissues.
Secrete CSFs, IL-5 and IL-7.
Promotes different lineage development from the HSC.
In between the sinusoids are the actually bone marrow tissues that is functionally active in producing blood cells–known as cords

Question 9

How do the newly formed cells of the hematopoietic islands get out into the circulation?

Answer 9

1. cells become associated with a sinusoid
2. they pierce through the endothelial wall and make a whole
3. squeeze through hole
4. get into circulation
5. opening self seals that only cells that are ready can leave

Question 10

What does the cellularity of bone marrow represent?

Answer 10

The ratio of hematopoietic cells to adipocytes

Question 11

How is normal cellularity calculated?

Answer 11

Subtracting an individuals age from 100 and adding plus or minus 10%

Question 12

What conditions correspond with hypocellular marrow?

Answer 12

aplastic anemia, chemo

Question 13

What conditions correspond with hypercellular marrow?

Answer 13

acute myo leuk

Question 14

What is hypercellular marrow?

Answer 14

bone marrow affected by hematopoietic cell tumors– when marrow is chalk full!

Question 15

What is hypocellular marrow?

Answer 15

when only a small number of blood-forming cells are found

Question 16

What are the three major groups of hematopoietic growth factors?

Answer 16

Colony Stimulating Factors, EPO + TPO (this is specific to the megakaryocyte lineages), and interleukin (3, 2, 6, and more)

Question 17

Which progenitor cell differentiates into lineage-restricted progenitors?

Answer 17

Common myeloid progenitors

Question 18

What is erythropoiesis regulated by?

Answer 18

EPO–> this is released in response to low SpO2 levels

Question 19

The process of a CMP becoming a MEP required what influences?

Answer 19

EPO, IL-3, and IL-4. The MEP will then go and divide into a ErP

Question 20

What txn factor is required for terminal differentiation to erythroid lineage?

Answer 20

GATA-1. The need for GATA-1 comes after the need for EPO, IL-3, and IL-4

Question 21

What is unique about the morphology of the megakaryocyte?

Answer 21

This cell has massive amounts of nuclear material due to the repetitive chromosomal duplication of the nucleus

Question 22

GMPs use GM-CSF and IL-3 to differentiate in order to form what kind of cells

Answer 22

neutrophiles, eosinophils, basophils, and monocyte production

Question 23

How are eosinophil progenitors different from basophilic progenitors?

Answer 23

Both need GM-CSK but eosinophil progenitors and need both IL-3 and IL-5 but basophilic progenitors only need 3