74. heamatopoisesis

Question 1

what is haematopoiesis

Answer 1

Formation of blood cells that come from a single type of hemopoietic stem cell (HSC) in bone marrow

Question 2

what is its purpose

Answer 2

makes new blood cells to replace old blood cells so you have a steady blood supply

Question 2

what kind of properties do the haempotesis stem cells have

Answer 2

self renewal. - when they poliferste some daughter cells remain as these stem cells so they ae not depleted

Question 3

what are progenitor cells

Answer 3

descendants of stem cells that can differentiate to a specialized cell, however has a limited amount that it ca divide.

Question 4

what are all blood cells divided into

Answer 4

lineages:
■Erythroid (RBC)
■ Thrombocytic (megakaryocytes for platelet
formation)
■ Granulocyte-monocyte (granulocytes
and monocytes)
■ Lymphoid (B, T lymphocytes)

Question 5

what is name of Hemopoietic growth factor and what does it do.

Answer 5

colony stimulating factors (CSF)
Stimulates proliferation of progenitor and precursor cells
and promote cell differentiation and maturation within specific lineages

Question 6

Periods of haemopotesis what is it

Answer 6

when stem cell matures + changes in gene expression.
changes can include different proteins on cell surface which showscell is getting closer to its final cell type.

Question 7

what do proliferation and self renewal depend on?

Answer 7

growth factors. key player of development of hematopoietic cells = stem cell factor.

Question 8

What do CSFs stimulate

Answer 8

granulocyte formation and active on progenitor cells,
erythropoietin needed for myeloid progenitor to become erythrocyte.
Thrombopoietin makes myeloid progenitor to differentiate to megakaryocytes.

Question 9

what do cytokines do

Answer 9

control proliferation, differentiation, survival and death of progenitor cells. therefore maintains steady levels of blood cells

Question 10

what does a HSC turn into?

Answer 10

1. myeloid progenitor
   - myoblast - then bas, neut, eosinophil, monocytes
   - erythrocytes + platelets
2. lymphoid progenitor
   - lymphoblast - then T+ B lymphocytes

Question 11

Sites of haematopoiesis

Answer 11

developing embryos blood formation occurs in yolks sac.
then in spleen, liver, lymph nodes.
In children haematopoiesis in marrow of long bones, adults in pelvis, cranium vertebrae sternum.