Flashcards in Physiology of Haematopoiesis Deck (117)
What is haematopoiesis?
The process through which all types of mature blood cell are produced
What are haematopoietic stem cells (HSCs)?
Multipotent cells characterised by their ability to 'self-renew' (proliferate) and mature into fully differentiated cells of any of the haematopoietic lineages
What is the importance of HSCs?
They sustain blood cell production throughout life
What are the principle haematopoietic lineages?
What does the erythroid/megakaryocytic lineage give rise to?
What does the granulocyte/macrophage lineage give rise to?
Granulocytes and monocytes
What does the lymphoid lineage give rise to?
- B cells
- T cells
- NK cells
What can HSCs be characterised by?
Proteins expressed on the cell membrane
What can the cell markers on the membrane of HSCs be utilised for clinically?
To purify HSC for clinical applications, e.g. haematopoietic stem cell transplant
What are the HSCs and their progeny controlled by?
A network of interactions with haematopoietic growth factors and cellular components of the haematopoietic micro-environment that maintain balanced blood cell production
When does primitive haematopoiesis begin?
In the first few weeks of embryonic life
Where does primitive haematopoiesis begin?
In the yolk sac
What does primitive haematopoiesis give rise to?
What is primitive haematopoiesis replaced by?
When is primitive haematopoiesis replaced by definitive haematopoiesis?
5-6 weeks gestation
What does definitive haematopoiesis produce?
Has the capacity to produce all blood cell cycles
Where do definitive hematopoietic stem cells develop?
In the aorta-gonad-mesonephros (AGM) region of the dorsal aorta
Where do HSCs migrate after developing in the AGM?
To the fetal liver and spleen
When do HSCs migrate from the AGM region to the fetla liver and spleen?
6-7 weeks gestation
What is the primary site of haematopoiesis from 6-7 weeks gestation?
What happens to the site of haematopoiesis in the third trimester?
It progressively increases in the bone marrow
What is the site of haematopoiesis after birth?
Where in the bone marrow does haematopoiesis occur?
Initially it occurs in all areas of the bone marrow, but becomes restricted to axial skeleton and proximal ends of long bones later in childhood
What are RBCs?
Specialised cells that mainly function to deliver oxygen to the tissues and remove carbon dioxide
What shape are RBCs?
What cellular structure do RBCs lack?
What do RBCs have a lot of?
The oxygen-carrying protein haemoglobin
What does each molecule of haemoglobin consist of?
4 globin chains and a central iron containing haem group
What happens to the composition of Hb during fetal development?
It changes in an ordered sequence