Haemopoiesis Flashcards
What is haematology?
The study of blood, blood-forming tissues, and the disorders associated with them.
What is the role of haematology in the provision of UK healthcare?
- 4% of the healthcare budget expenditure
- More tests and test types than ever
- Primary care - GP
- Secondary care - haematology department at a hospital
- Tertiary care - specialist haematology department at a hospital
Which pathology disciplines overlap with haematology?
- Blood transfusion
- Immunology
- Clinical biochemistry
- Microbiology
- Histopathology
- Cytology
- Genetics
- Stem cell laboratories
What is haemopoiesis?
The process of blood cell and platelet formation.
What are the basic cellular components of blood and their functions?
- Red blood cells - carry oxygen to tissues
- White blood cells - prevent and respond to infection
- Platelets - blood clotting
Red blood cell profile
- Most numerous blood cell
- Normal range 4-5.5 trillion /litre
- 6.7-7.7 micrometres diameter biconcave disc
- Contains haemoglobin
- Carries O2 from lungs to tissues
- Carries CO2 from tissues to lungs
- Lives for 110-120 days in the blood
White blood cell profile
- Least numerous blood cells
- 3.5-10 billion per litre
- 5 different types
- Lymphocytes
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
Granulocyte profile
A type of white blood cell
- Neutrophils
- Eosinophils
- Basophils
Neutrophil profile
- Normal range 1.5-7.5 billion per litre
- Fights bacterial infection
- Tri-lobed
- Fine faint granules
- Pus cells
- Phagocyte
- 7 hour circulation half-life
Eosinophil profile
- Normal range 30-600 million per litre
- Bi-lobed
- Coarse orange granules
- Release histamine in allergic reactions
- Regulate hypersensitivity reactions
- Effector cells for antibody-dependent damage to parasites
Basophil profile
- Normal range 10-150 million per litre
- Bi-lobed
- Dark coarse azurophilic granules
- Granules contain enzymes
- Moderates inflammatory response
- Releases heparin and protease
Lymphocyte profile
- Normal range 1.2-3.5 billion per litre
- Fights viral infection
- Produces antibodies
- Circulates between blood and lymphatic system
- Life span from a few hours to 4-5 years in circulation
Monocyte profile
- Normal range 200-800 million per litre
- Fights bacterial infection
- Phagocytoses bacteria and antibody-coated cells
- Tissue macrophage precursors
- 70 hour lifespan
Platelets profile
- Normal range 150-400 billion per litre
- Second most numerous cells in blood
- Small discoid structures
- 3-5 micrometers diameter
- Circulation lifespan of 7-10 days
- Important in blood clotting (haemostasis)
- Form a plug at injury site (primary haemostasis)
- Initiate secondary haemostasis
What are the sites of haemopoiesis?
- Yolk sack in a 2 week old embryo
- Liver and spleen of a 12-16 week old embryo
- The bone marrow of all bones in newborns
- Ends of long and flat bones such as the sternum, pelvis and vertebrae in adults
- Red marrow - active
- Yellow marrow - inactive
Three steps involved in haemopoiesis
- Proliferation - multiplication
- Differentiation - changing form and function
- Apoptosis - programmed cell death
How is haemopoiesis regulated?
By glycoprotein growth factors that inhibit apoptosis
What are the two main classes of growth factors involved in haemopoiesis?
- Colony stimulating factors
- Interleukins
