Red Blood Cells - Haemopoiesis

Question 1

Origin of blood cells

Answer 1

Derived from pluripotent haemopoeitic stem cells (HSCs)
—> give rise to:
- lymphoid stem cells —> lymphocytes
- myeloid stem cells —> red cells, platelets…

Question 2

Haemopoieisis

Answer 2

Formation and development of blood cells

Question 3

Two essential characteristics of HSC

Answer 3

1. Self-renew
2. Differentiate to mature progeny

Question 4

Sites of haemopoiesis

Answer 4

Yolk sac - 3 wks

Liver - 6-8 wks gestation

Bone marrow ~ 10 wks gestation

Question 5

Haemopoietic progenitor cells - where are they and how are they regulated?

Answer 5

HSCs and progenitor cells are distributed in an ordered fashion within the bone marrow

Regulated by a number of genes, transcription factors, growth factors and the micro environment
—> distruption can disturb balance between proliferation and differentiation
—> leukaemia or bone marrow failure

Question 6

Haemopoietic growth factors - what are they and what do they do?

Answer 6

Glycoprotein hormones —> bind to cell surface receptors

Regulate proliferation and differentiation of HSCs

Regulate function of mature blood cells