Stem cells/Haematopoiesis

Question 1

totipotent?

Answer 1

can form any cell in embryo

Question 2

pluripotent?

Answer 2

differentiate into cells formed from 3 germ layers.

Question 3

multipotent?

Answer 3

produce cells of a closely related family of cells.

Question 4

long term repopulating cells?

Answer 4

capable of producing all blood cell types for the entire life span.

Question 5

short term repopulating cells?

Answer 5

reconstitute myeloid and/or lymphoid compartments for a short period of time

Question 6

how do HSC lie normally?

Answer 6

in a quiescent state until they receive signals from the surrounding “niche” to become activated

Question 7

what are induced pluripotent stem cells?

Answer 7

-iPS cells are adult somatic cells that are “reprogrammed” into stem cells - reversing the differentiation process of specialised cells that they become undifferentiated again

Question 8

biggest advantage of iPS?

Answer 8

less likely for immune system to reject transplantation as cells are “Self”

Question 9

how much of blood does haematocrit make up?

Answer 9

45%

Question 10

how are rbc’s replenished?

Answer 10

proliferation and differentiation of hematopoietic stem cells.

Question 11

what is haematocrit?

Answer 11

chunky stuff in blood.

Question 12

how much of blood is plasma?

Answer 12

55%.

Question 13

what is most primitive blood cell?

Answer 13

haematopoietic stem cells

Question 14

what are multipotent progenitors (MPP)?

Answer 14

forms both myeloid progenitor and lymphoid progenitor precursors.

Question 15

what are bipotential progenitors?

Answer 15

B cells, T cells, macrophages.

Question 16

what happens to proliferative potential as cells differentiate?

Answer 16

decreases, but frequency and turnover increases.

Question 17

what does forward scatter refer to?

Answer 17

size of cells.

Question 18

what does side scatter refer to?

Answer 18

complexity of cells.

Question 19

haematopoiesis in embryo?

Answer 19

• 1 month - yolk sac and aorta gonad mesonephros (AGM) contains HSC which migrate into bone marrow.
• 3 months - foetal liver and spleen develop
• 5 months - first bone marrow cavities form.

Question 20

what are the different ways of HSC commitment?

Answer 20

• stochastic - random commitment to particular lineage

- instructive - determination of cell-cell contact.

Question 21

what transcription factor is involved in myeloid cell production?

Answer 21

PU1

Question 22

What transcription factor is involved in erythroid development and regulation?

Answer 22

GATA-1

Question 23

What happens if transcription factors are activated?

Answer 23

more receptors are produced on the cells surface, increased response to growth factors and thus increased lineage commitment/differentiation.

Question 24

what do colony stimulating factors do?

Answer 24

influence multiplication and differentiation of hematopoietic stem cells.

Question 25

features of CSF?

Answer 25

- can be specific for cell lineage or may influence multiple lineages. - CSF's bind to receptors to initiate signalling cascades within cells.

Question 26

how are CSF's used in chemo?

Answer 26

- used to accelerate recovery of blood. - in chemo, rapidly dividing cells such as blood cells may become damaged, CSF may help recover some of the damaged cells.

Question 27

what does gM-CSF do?

Answer 27

mobilise stem cells - further aid in recovery.

Question 28

what happens as we get older?

Answer 28

-proportion of fat cells in the bone marrow increases and HSC decrease.

Question 29

what happens in disease states?

Answer 29

the spleen or liver may try to accomodate RBC production which can lead to organ enlargement

Question 30

what is in stomal cells?

Answer 30

1. reticular fibroblasts 2. adipocytes 3. osteoblasts 4. osteoclasts.

Question 31

what is in haematopoietic cells?

Answer 31

1. erythroblasts 2. megakaryocytes 3. lymphocytes/granulocytes 4. macrophages

Question 32

What are megakaryoblasts?

Answer 32

stem cells that develop receptors for thrombopoietin (for platelet production)

Question 33

what does megakaryoblasts do to form megakaryocytes?

Answer 33

repeatedly replicates its DNA without dividing to form gigantic cell called megakaryocyte.

Question 34

how are platelets formed from megakaryocytes?

Answer 34

megakaryocyte cytoplasm splits off cell fragments that enter the bloodstream as platelets.

Question 35

what does haemopoiesis arise from?

Answer 35

multipotent stem cells in bone marrow

Question 36

order of formation?

Answer 36

stem cells progenitor cells red cells, granulocytes, (neutrophils, eosinophils, basophils), monocytes, platelets, B and T lymphocytes.

Question 37

rbc development?

Answer 37

hsc proerythroblast reticulocyte erythrocyte

Question 38

what does proerythroblast have?

Answer 38

receptors for epo