Introduction to haematology Flashcards
What is haemopoiesis?
Physiological developmental process giving rise to cellular components of blood
What is the first cell in haemopoiesis?
Haemopoietic stem cell
What are the 4 facts of haemopoietic stem cells?
Symmetric self renewal - increase stem cell pool, no generation of differentiated progeny
Asymmetric self renewal - maintenance of stem cell pool and generation of differentiated progeny
Lack of self renewal - increased generation of differentiated progeny, reduced stem cell population
Lack of self renewal - maintenance of stem cell pool RESTING STATE
What are the characteristics of haemopoietic cells that make them suited for their function/
Differentiation potential for all lineages
High proliferative potential
Long term activity throughout lifespan
Self renewing
What are the 2 broad lineages of haemopoiesis?
Myeloid - granulocytes, erythrocytes, platelets
Lymphoid - B lymph, T lymph, NK cells
When does haemopoiesis first start and where?
Day 27
AGM (aorta gonad mesonephros)
At day 40, haemopoiesis disappears at the AGM, why?
Migration of haemopoietic stem cells from AGM to foetal liver (which becomes site of haemopoiesis)
What is the lifespan of a erythrocyte?
120 days
What do the following terms mean?
Anaemia
Polycythaemia
Relative polycythaemia
- Reduced RBCs
- Increased RBCs
- Reduced plasma volume (therefore ratio of RBC:plasma increases)
What is the term meaning reduced number of neutrophils?
Neutropaenia
What is the term meaning increased neutrophils?
Neutrophilia
How long do neutrophils last in the bloodstream?
4-6 hours
What circumstances does eosinophilia occur?
- Parasitic infections
- Allergies
What condition could basophilia indicate?
Chronic myeloid leukaemia
What is the term meaning increased number of monocytes?
Monocytosis
What could increased number son monocytes in the blood indicate
Infection e.g. TB
What do Natural killer cells do?
Large granular cells (innate immunity) that recognise non-self cells
What are the function of B lymph?
Part of adaptive immune system, they rearrange immunoglobin genes to enable specific antibody production
What are the function of T cells?
T helper and Cytotoxic T cells
What does lymphocytosis mean?
Increased number of lymphocytes
e.g. atypical lymphocytes of glandular fever; chronic lymphocytic leukaemia
What does lymphopenia mean?
Reduced number of lymphocytes e.g. post bone marrow transplant
What does plasmacytosis mean?
Increased number of plasma cells e.g. infection, myeloma
What cells do platelets cells originate from?
Megakaryocyte
What are the 4 main subdivisions of haematology?
Coagulation
Malignant
Non-malignant
Transfusion
What information can you get from a FBC?
Hb conc Red blood cell count - Mean cell volume - mean cell Hb Platelet White blood cell
What are the normal FBC ranges?
Hb (g/l)male = 135-180; F 115-160 WBD 4-11 Platelets - 150-400 MCV - 78-100 MCH - 27-32
What tis the information you receive from a coagulation screen?
Prothrombin time
Activation partial thromboplastin time
Thrombin time
When blood is extracted, how is it treated in the tube?
EDTA anticoagulant
What is meant by test sensitivity?
Degree to which tests picks up TRUE ABNORMALITIES (i.e. true negatives)
TP/(TP+FN)
What does test specificity tell us?
The proportion of normal test results correctly classified by a test
TN/(TN+FP)
What are the three main types of anaemia?
Microcytic (smaller), homochromic (paler)- (low MCV, MCH)
normocytic, norochromic
(normal MCV, MCH, but actual Hb is low)
Macrocytic
(greater MCV)
What can cause microcytic hypo chromic anaemia?
Iron deficiency*
Thalassaemia
Lead poisoning
What can cause normocytic, norochromic anaemia?
Acute blood loss
Renal disease
Bone marrow failure
Mixed deficiencies (folate, B12, iron)
What can cause macrocytic anaemia?
Megaloblastic (abnormality of division deficiency/proliferation in haemopoetic) - vit B12, folate deficiency
Non-megaloblastic - alcohol abuse, liver disease
