Haematopoiesis Flashcards
What is haematopoiesis?
Production of RBCs
Leucocytes and platelets produced in haemopoietic tissue
What happens to ageing or damaged blood cells?
Cell components recycled or removed by macrophage
Give an example of when there might be a haematopoiesis arrest. What is the first clinical sign of this?
Chemotherapy
Neutrophenia
What is the lifespan of an RBC?
1-5 months
Bird
What is the lifespan of platelets?
10 days
Put the blood cells in order of longest to shortest life span
Lymphocytes - weeks to years
RBCs - 1- 5 months
Platelets - 10 days
Monocytes - days, transform into macrophages in tissues
Neutrophils - live less than 10 hours in blood, 24-48 in tissues
Which WBC has the longest and shortest life span?
Longest - lymphocyte (weeks to years)
Monocytes live days, transform into macrophages in tissues
Shortest - neutrophils (<10 hrs in blood, <2 days in tissue)
Where is the major site of haematopoiesis?
Bone marrow
Primary in long and flat bones
First evident in yolk sac of embryo
Later in embryonic life occurs in liver and spleen
Birth = red bone marrow (long bone, vertebrae, pelvis, skull
What cells are found in bone marrow?
Endothelial cell Macrophage Stromal cell Developing granulocytes Megakaryocyte
What do stromal cells in bone marrow produce?
Haematopoietic regulatory molecules
What are the 2 cells that multipotent haematopoietic stem cells can form?
Common myeloid progenitor
Common lymphoid progenitors
What cells do common lymphoid progenitors form?
All lymphocytes:
Natural killer cell Small lymphocyte (which forms T and B lymphocytes)
What cells do common myeloid progenitors form? 4 cells - all begin with M except one
Give rise to all other blood cells (not lymphocytes as thats what lymphoid progenitors give rise to) RBC Mast cell Megakaryocyte Myeloblast
Which cells produce WBCs?
Myeloblast
Bone marrow is only part of lymphogenesis (production of lymphocytes). Where do they migrate to, mature and proliferate?
Lymphoid organs - lymph nodes, thymus, spleen
What feature makes T and B lymphocytes unique (after antigen encounter)?
Maintain memory of an antigen encounter
What are reactive lymphocytes?
Cytotoxic lymphocytes made due to antigen stimulation
What is myelopoieses? What main cell does this arise from?
Production of all blood cells
Common myeloid progenitor
Where does myelopoiesis take place?
Bone marrow
Proliferative pool, maturation pool and storage pool
What cells are mainly found in the storage pool of bone marrow?
Mature (segmented) neutrophils
What stimulates granulocytopoiesis and monocytopoiesis? When are these produced?
Granulocyte-macrophage colony stimulating factor (GM-CSF)
Macrophage colony stimulating factor (M-CSF)
Presence of infection or inflammation
Which cells are able to provide negative feedback to their own production?
Neutrophils
In homeostasis, what neutrophils are seen in circulation? When may other types of neutrophil be seen?
Segmented (mature neutrophils) Band cells (immature neutrophils) released with inflammation
How does number of neutrophils in circulation differ between moderate inflammation and very acute severe inflammation? Why?
Mild/moderate inflammation - neutrophiliia due to release from storage pool and increased myelopoiesis
Acute, severe inflammation - neutropenia, due to consumption of neutrophils
