Haematopoiesis

Question 1

Haematopoiesis

Answer 1

Production of blood cell in an appropriate number, with the ability to adapt to requirements and respond rapidly/effectively

Question 2

Erythrocyte

Answer 2

RBC

Question 3

Leukocyte

Answer 3

WBC

Question 4

Thrombocytes

Answer 4

Platelets

Question 5

Hematopoietic stem cell

Answer 5

Multipotent stem cell responsible for all blood cell.

Question 6

Briefly describe myeloid lineage

Answer 6

Hematopoietic cell to myeloid progenitor to either megakaryocyte (platelets), erythrocyte, mast cell and myeloblast (basophil, eosinophil, neutrophil, monocyte –> macrophage. )

Question 7

Briefly describe lymphoid lineage

Answer 7

Hematopoietic cell to lymphoid progenitor to either natural killer cells or small lymphocytes (T and B cells)

Question 8

What are granulocytes?

Answer 8

Eosinophils, neutrophils, basophils. Have granules that can directly kill invading organisms.

Question 9

RBC life span

Answer 9

120 days (35 shelf life span)

Question 10

WBC life span

Answer 10

5-10 days

Question 11

Name three cytokines needed for haematopoiesis?

Answer 11

Erythropoietin= increases RBC  production
G-CSF= increases WBC neutrophil
Thrombopoietin= increase platelet.

Question 12

How are RBC increased?

Answer 12

Erythropoietin is secreted when oxygen level goes down. O2 level detected in kidney. EPO acts on precursors to enhance survival and increase maturation rate. (Can be artificially injected).

Question 13

How are neutrophils increased?

Answer 13

Neutrophils has natural baseline. Infection causes G-CSF to be secreted from endothelial cells. Increases survival and maturation acts on granulocyte precursor.

Question 14

How are platelets increased?

Answer 14

Thrombopoietin (TPO) produced in kidney and liver produced constantly but increases in inflammation. Acts on megakaryocytes..

Question 15

How is TPO stopped?

Answer 15

Negative feedback, platelets destroy TPO.

Question 16

Describe long term control of blood production

Answer 16

Stem cells can either self renew or differentiate into a lineage.

Question 17

What prevents haematopoietic stem cell from proliferating into cancer

Answer 17

There aren’t many stem cells, cell division is low, and division is highly controlled. But enough blood cells are still made as 20 generation are made. So 1 stem cell makes 500,000.

Question 18

Stem cell niche

Answer 18

A niche of proteins and cells that the stem cells require to survive. Die without the niche.

Question 19

How many cell divisions in haematopoiesis result in cell death?

Answer 19

40%

Question 20

Whats the point of cell deaths

Answer 20

Naturally occurring cell deaths mean that by stopping cell death the number of cells can increase quickly. Cytokines control the cell lineage