Haematopoiesis Flashcards
What are the only cells that can replicate? [1 mark]
Stem cells
Where are the sites of haematopoiesis? [4 marks]
IN EMBROYS: Yolk sac
IN FOETUSES: Foetal liver
IN INFANTS: Bone marrow
IN ADULTS: Central skeleton
What is the reason for red marrow’s colour? [2 marks]
- Site of active haematopoiesis
- Red due to haemoglobin
What is the reason for yellow marrow’s colour? [1 mark]
Filled with fat cells
What is a trephine biopsy? [2 marks]
- Drilling a needle into the iliac crest and taking a core of the bone marrow
- Sample is placed in wax then sectioned
What is a bone marrow aspirate? [3 marks]
- Sample from iliac crest is obtained under local anaesthetic
- Sample is smeared onto a slide
- You can see the structure of cells much clearer
What does it mean when your reticulocyte count is high? [1 mark]
You may have haemoglobin anaemia
Where do platlets come from? [1 mark]
Megakaryocytes
Where do lymphocytes come from? [1 mark]
Lymphoid cells
Where do T lymphocytes originate from? [1 mark]
Thymus (in chest)
Where do B lymphocytes originate from? [1 mark]
Bone marrow
What happens to lymphocytes during development (genetic change)? [1 mark]
Gene rearrangement (T cell receptor and immunoglobin gene)
What are colony assays? [3 marks]
- Bone marrow samples placed in a semi-solid medium (e.g. agar)
- This is alongside growth factors
- Progenitors (colony forming units) grow to form colonies
What are the different types of preogenitors? [7 marks]
- CFU-G: granulocyte (more accurately, neutrophils)
- CFU-GM: granulocyte/monocyte
- CFU-E: erythroid
- CFU-Mk: megakaryote
- CFU-bas: basophil
- CFU-eo: eosinophil
- BFU-E: burst forming unit-erythroid
What are factors that stimulate colony growth? [3 marks]
- G-CSF (granulocyte colony stimulating factor)
- M-CSF (monocyte colony stimuating factor)
- GM-CSF (granulocyte/macrophage colony stimulating factor)
Bone marrow transplantation process [3 marks]
- Eradicate haematopoiesis
- Onfuse donor bone marrow cells (HLA matched)
- Haematopoiesis restored in 3-4 weeks
When is bone marrow transplantation appropriate? [3 marks]
- For leukaemia, lymphoma, myeloma
- Chemotherapy for solid tumours
- Thalassaemia or SCID)
Risks of bone marrow transplant [3 marks]
- Infection due to neutropenia (low neutrophil count)
- Bleeding due to thrombocytopenia (low platlets)
- Graft versus Host disease (where graft attacks the body organs)
Alternative to bone marrow transplant [1 mark]
Give G-CSF to mobilise stem cells and then harvest them
What is chronic myeloid leukaemia caused by? [2 marks]
- A chromosome translocation between chromosome 9 and 22
- Causes excess production of neutrophils & neutrophil precursors
What is erythropoietin and what is its functions? [2 marks]
- Produced in the kidneys in response to hypoxia
- Increases RBC production by increasing survival of erythroid progenitors (CFU-E)
What are the clinical applications of erythropoietin? [2 marks]
- Treating anaemia of kidney failure
- Alternative to blood transfusion in Jehovah’s Witnesses
When is G-CSF produced? [1 mark]
In response to inflammation
What does G-CSF do? [2 marks]
- Chemoattractant that promotes neurophil maturation and activation
- Stimulates neutrophil production in the bone marrow
How are blood stem cells collected? [4 marks]
- Leukapheresis
- 2 needles are inserted into the arm
- Blood is run through a machine that picks out specific cells
- Rest of blood is returned to the donor
