Flashcards in Intro to Haemopoiesis Deck (9)
What is haemopoiesis?
- Haemopoiesis is the formation of red cells, white cells and platelets
- All of these cells are derived from haemopoietic stem cells
Describe the structure of the bone marrow (bone anatomy)
-The spongy bone in which haematopoiesis occurs is a reticulin connective tissue network like spiderweb with Mesenchymal Stromal cells, macrophages and other supportive cells to assist haemopoietic cells
-Bone marrow is about 50% empty space and 50% cells
Describe the function of the bone marrow (cellular)
• Normal bone marrow function
– production of
• red cells
• white cells
• nutrients including iron, B12, B6, folate, amino acids, energy
• supportive cells- stromal cells, cytokines
Normal bone marrow function
• Erythroid- includes ERYTHROPOIETIN
• Granulocytes- includes G-CSF, GM-CSF
• Lymphocytes- Interleukins
• Platelets- THROMBOPOIETIN
– Stromal Cells, Nucleic acids, amino acids etc.
What are cytokine cells and what do they do in haematopoiesis?
Cytokines are small proteins that are involved cell signalling
They are released by macrophages, lymphocytes, endothelial cells, fibroblasts and stromal cells, to affect the behaviour of other cells
In haematopoiesis, the presence of different cytokines dictate which cells are produced i.e. erythropoietin will induce the production of erythrocytes
Describe the differentiation of haemopoietic cells
HSC --> Common Myeloid Progenitor + Common Lymphoid Progenitor
Myeloid --> Megakaryocyte + Erythrocyte + Myeloblast
Megakaryocyte --> Thrombocytes
Erythrocytes --> RBC
Myeloblast --> Basophil, Eosinophil, Neutrophil, Monocyte
Lymphoid --> small lymphocyte --> T cells + B cells
The formation of blood cellular components, derived from haematopoietic stem cells in an appropriate nutritional environment (iron/B12 etc), with supporting cells
Characteristics of haemopoietic stem cells
Displays CD34 on the surface
What are some causes of decreased numbers of RBCs, WBCs and platelets?
Marrow failure syndromes, Iron/B12/Folate Deficiencies, Blood loss etc. Renal Failure with reduced production of EPO
– White cells
Viral Infections, Post Chemotherapy, Reduced G- CSF stimulation (rare, inherited)
Immune Destruction(ITP), Drugs etc.