Introduction to Haematology Flashcards
What is the definition of haematology?
Biology and pathology of the cells that normally circulate in the blood
What is the definition of haemopoiesis?
physiological developmental process that gives rise to the cellular components of the blood - starts in bone marrow
single multipotent haemopoietic stem cell can divide and differentiate to form different cell lineages
What are the features of Haemopoietic stem cells?
differentiates into all lineages
Long term activity throughout the lifespan of the individual
Self renewal
What are the 4 types of self renewal that can occur?
symmetric self revewal - duplication of identical cells to increase volume
asymmetric self-renewal - forms half stem and half mature cells
lack of self renewal - forms fully differentiated cells
lack of self renewal - does not differentiate
What are the two Haemopoietic Lineages?
Myeloid - WBC, RBC, platelets
lymphoid - B and T lymphocytes
What is another name for precursor cells?
committed cells
Where does haemopoiesis originate from?
starts on day 27
aorta gonad mesonephos region - vessel wall
stems cells then travel in the bloodstream and migrate into the foetal liver and that becomes the site of haemopoiesis
What is anaemia?
reduced red cells
What is polycythaemia?
raised red cells
What is relative polycythaemia?
plasma volume is reduced
What is the lifespan of the red blood cell?
120 days in the blood
What shape is a red blood cell?
bi-concave
What are the 3 types of ganulocytes?
neutrophils
eosinophils
basophils
What is the function of neurophils?
phagocyte
engulfs bacteria
What is neutophilia and when does it occur?
increased number of neutrophils
bacterial infection
inflammation
What is neutropenia and when can it occur?
decreased number of neutrophils
side effect of a drug - chemo
autoimmune disease
what is eosinophilia and when can it occur?
increased number of eosinophils
parasitic infection - schistosomiasis
allergies
drugs e.g. aspirin
what is basophilia and when can it occur?
increased number of basophilia
chronic myeloid leukaemia
What are monocytes?
phagocytic
antigen presenting cells
migrate to tissues the identified as macrophages or histiocytes
what is monocytosis and when can it occur?
increased number of monocytes
TB
What cells are lymphocytes?
Natural killer cells
B lymphocytes
T lymphocytes
Plasma cells
What do natural killer cells do?
innate immune system
large granular lymphocytes
recognises ‘non self’ cells i.e. viruses
What do B lymphocytes do?
humoral immunity
adaptive immune system
antigen specific antibody production
What do T lymphocytes do?
adaptive/cell mediated immune system rearrange T cell antigen receptors interact with B cells and macrophages regulate immune response uses cytotoxicity
What is lymphocytosis and when can it occur?
increased number of lymphocytes
chronic lymphocytic leukaemia
glandular fever - atypical
What is lymphopenia and when can it occur?
post bone marrow transplant
What is plasmacytosis and when can it occur?
increased number of plasma cells
infection
myeloma
What do platelets do?
forms part of blood clotting system
aggregate to plug holes in damaged blood vessels
where are platelets derived from?
bone marrow megakaryocytes
What is microcytic hypochromic anaemia?
low MCV
low MCH
When can microcytic hypochromic anaemia occur?
iron deficiency
thalassaemia
lead poisioning
Anaemia of some chronic diseases
What is normocytic normochromic anaemia?
MCV 80-95 (normal)
MCH >27 (normal)
Hb low
When can normocytic normochromic anaemia occur?
Many haemolytic anaemias Anaemia of chronic disease (some cases) After acute blood loss Renal disease Mixed deficiencies Bone marrow failure (e.g. post-chemotherapy, infitration by carcinoma etc)
What is macrocytic anaemia?
MCV > 95 (larger RBC)
When can macrocytic anaemia occur?
Megaloblastic: Vitamin B12 or folate deficiency
Non-megaloblastic: alcohol, liver disease, myelodysplasia, aplastic anaemia etc
