Haematology Flashcards
What is haemopoiesis?
-Physiological developmental process that gives rise to the cellular components of blood
Describe haemopoietic stem cells
- Differentiation potential for all lineages
- High proliferative potential
- Long term activity throughout the lifespan of the individual
- Self renewal
What is symmetrical self-renewal?
- One stem cell becomes 2 stem cells
- Inc stem cell pool
- No generation of differentiated progency
What is asymmetrical stem cells?
- One stem cell becomes a stem cell & a progenitor cell
- Maintains stem cell pool
- Generation of differentiated progency
What are the types of stem cells proliferation?
- Symmetric
- Asymmetric
- Lack of self-renewal
What happens in lack of self- renewal?
-One stem cell becomes 2 progenitor cells
-Deplete stem cell pool
-Generation of only differentiated progency
Or
-No stem cell division so maintains stem cell pool
What are the haemopoietic lineages?
- Myeloid= Granulocytes, platelets, erythrocytes
- Lymphoid= B/T lymphocytes
What are the origins of haematopoiesis
1) Ovum becomes trophoblast
2) 9days first signs of haemopoiesis
3) day 27 cells in aorta gonad mesonephros region expand rapidly
4) Disappears at day 40
5) Migration of heamatopoietic stem cells to the foetal liver
6) Becomes subsequent site of haematopoiesis
What is the function of blood cells?
- O2 transport
- Coagulation
- Immune response to infection
- Immune response to abnormal cells (malignancy)
What do granulocytes contain?
-Cytoplasmic granules: Neutrophils, basophils, eosinophils
Describe clinical changes in eosinophil count
basophil count
monocyte count
neutrophil count
- eosinophilia- parasitic infection, allergies
- basophilia- chronic myeloid leukaemia
- monocytosis- TB
- Most common. Inc no= neutrophilia- bacterial infection, inflammation, neutropenia
What are Natural killer cells?
- Innate immune system
- Large granular lymphocytes
- Recognise ‘non-self’ cells, viruses
What are B-lymphocytes?
- Adaptive immune system
- Rearrange immunoglobulin genes to enable antigen specific antibody production
- Humoral immunity
What are T-lymphocytes?
- Adaptive immune system
- Rearrange T cell antigen receptors
- Cell-mediated immunity
- Target specific cytotoxicity
- Regulate immune responses
- Interact with B cell macrophages
What is lymphocytosis & lymphopaenia?
- Cytosis= Inc lymphocytes: glandular fever, chronic lymphocytic leukaemia
- Penia= dec no. Post bone marrow transplant
What are clinical changes in plasma cells?
Plasmacytosis- inc no= infection, myeloma
-Platelets derved from bone marrow megakaryocytic
What are diagnostic tests in haematology? Describe
- FBC (Haem conc, MCV, MCH, WCC, platelet count)
- Blood film/smear
- Coagulation screen (time taken for a clot to form when mixed with plasma, prothrombin time, thrombin time, activated partial thromboplastin time)
Define sensitivity
- Proportion of abnormal results correctly classified by the test
- Expresses the ability to detect a true abnormality
Define specificity?
- Proportion of normal results correctly classified by the test
- Expresses the ability to exclude an abnormal result in a healthy person
How is anaemia classified?
-MCV
What are normocytic normochromic anaemias?
- MCV 80-95 MCH> 27
- Anaemia of chronic disease
- After acute blood loss
- Renal disease
- Mixed deficiencies
- Bone marrow failure (post-chemo, carcinoma)
What are macrocytic anaemias?
- MCV>95
- Megaloblastic: Vit B12 or folate deficiency (hyerpsegmented neutrophils & oval macrocytes)
- Non-megaloblastic: alcohol, liver disease, aplastic anaemia, myelodysplasia
What is the role of globin?
- Protects haem from oxidation
- Permits variation inO2 affinity
- Makes molecule soluble
What are normal blood ranges?
- WBC=4-11
- Platelets=150-400
- MCV=78-100
- MCH=27-32
- Neutrophils=2-7.5
- Lymphocytes=1-4.5
- Haemoglobin M=135-180 F=115-160
