14 - Haemopoiesis Flashcards
A haemopoietic stem cell can differentiate into what two common progenitor cells?
- Common myeloid progenitor
- Common lymphoid progenitor
What cell types are formed from the common myeloid progenitor?
- Megakaryocyte (platelets)
- Erythrocyte
- Mast cell
- Myeloblast:
> Basophil
> Neutrophil
> Eosinophil
> Monocyte –> Macrophage
What cell types are formed from the common lymphoid progenitor?
- Natural killer (large granular lymphocyte)
- Small lymphocytes (T cells and B cells)
Not all the cells in the bone marrow end up in the blood, what process removes the cells that aren’t required?
Apoptosis
What hormone is responsible for common myeloid progenitor differentiation into a megakaryocyte?
Thrombopoietin
What hormone is responsible for common myeloid progenitor differentiation into an erythrocyte?
Erythropoietin
What moelcules are responsible for common lymphoid progenitor differentiation into T cells and B cells?
Interleukins
What is the lifespan of an erythrocyte?
120 days
How are erythrocytes specialised for oxygen transport?
- Biconcave shape increases surface area
- Minimal organelles to maximise space
- No mitochondria so oxygen is not used up (only use anaerobic respiration)
- Haemoglobin to increase affinity of oxygen binding
Summarise the process of erythropoiesis.
- Proerythroblast formed in bone marrow
- Matures to erythroblast in bone marrow, intially have a large nucleus and lots of RNA but nucleus gradually shrinks and RNA is removed (except what is needed to make haemoglobin)
- Nucleus is removed to form a reticulocyte
- Enters peripheral blood and matures to an erythrocyte
What precursor to RBCs can be found in the blood in a high number during recovery from blood loss?
Reticulocytes (final step before RBC)
What is erythropoietin? When and where is it produced?
A glycoprotein that increases the levels of RBCs. Stops apoptosis of erythrocyte progenitors.
Produced by the kidneys in response to tissue hypoxia. Made in the liver during foetal life.
What factor is responsible for myeloblast maturation into neutrophils?
Granulocyte colony stimulating factor (G-CSF)
What are granulocytes?
A sub-group of white blood cells, named due to presence of granules in the cytoplasm
- Neutrophils
- Basophils
- Eosinophils
What is a neutrophil? What does it do?
- Multi-lobed nucleus
- 3 types of granules
- Most abundant of granulocytes
- First line of defence
- Kills bacteria in multiple ways