Blood Constituents and Haemopoiesis Flashcards
What is the production of blood cells termed?
Haemopoiesis
What are blood cells derived from?
Pluripotent stem cells, capable of making all the different types of blood cells
What are the sites of haematopoiesis in the embryo?
Yolk sac then liver
3rd to 7th month- spleen
What are the sites of haematopoiesis at birth?
Mostly bone marrow, liver and spleen when needed
What are the sites of haematopoiesis from birth to maturity?
Number of active sites in bone marrow decreased but retain ability to haematopoiesis
What are the sites of haematopoiesis in adults?
Bone marrow of skull, ribs, sternum, pelvis and proximal ends of femur
How many red cells are made per minute?
100 million
How many neutrophils are made per minute?
60 million
How many platelets are made per minute?
150 million
What has to happen to a stem cell to make blood?
Proliferation
Differentiation (cell development)
Most stem cells sit in a quiescent state
What is the progression of maturation to mature neutrophils seen in the marrow?
Myeloblast to promyelocyte to myelocyte through metamyelocyte forms eventually to band forms and neutrophils that are seen in the blood
What is the progression of maturation to mature red cell (erythropoiesis)?
Pronormoblast Basophilic/early normoblast Polychromatophilic/intermediate normoblast Orthochromatic/late normoblast Reticulocyte Mature red cell/erythrocyte
What are the granulocytes?
Eosinophils
Basophils
Neutrophils
What is the structure of neutrophils?
Segmented nucleus (polymorph) Neutral staining granules
What is the function of neutrophils?
Short life in circulation- transit to tissues
Phagocytose invaders
Kill with granule contents and die in the process
Attract other cells
What increases the number of neutrophils?
Body stress- infection, trauma, infarction
What is the structure of eosinophils?
Usually bi-lobed
Bright orange/red granules
What is the function of eosinophils?
Fight parasitic infections
Involved in hypersensitivity
What can elevate the numbers of eosinophils?
Patients with allergic conditions (e.g. asthma, atopic rhinitis)
What is the structure of basophils?
Infrequent in circulation
Large deep purple granules obscuring nucleus
What is the function of basophils?
Circulating version of tissue mast cell
Mediates hypersensitivity reactions
FcReceptors bind IgE
Granules contain histamine
What is the structure of monocytes?
Large single nucleus
Faintly staining granules, often vacuolated
What is the function of monocytes?
Circulate for a week and enter tissues to become macrophages
Phagocytose invaders- kill them, present Ag to lymphocytes
Attract other cells
More long lived than neutrophils
What is the structure of lymphocytes?
Mature – small with condensed nucleus and rim of cytoplasm
Activated (often called atypical) – large with plentiful blue cytoplasm extending round neighbouring red cells on the film, nucleus more ‘open’ structure
What is the function of lymphocytes?
Numerous types and function (B, T, NK)
Cognate response to infection
Brains of immune system
What will immunophenotyping show?
Expression profile of proteins (antigens) on the surface of cells
What will bio-assays show?
Culture in vitro and show lineage of progeny in different growth conditions
What are the posterior iliac crests common sites for?
Bone marrow aspiration and biopsy
