Week 10 Intro to haematology Flashcards
Define haematology?
Biology and pathology of the cells that normally circulate in the blood
What is Haemopoiesis?
The physiological developmental process that gives rise to the cellular components of blood
What can single multipotent haemopoietic stem cell differentiate into?
They can divide and differentiate to form different cell lineages that will populate the blood
What is the characteristic of haemopoietic Stem Cell?
Differentiation potential for all lineages
High proliferative potential
Long term activity throughout the lifespan of the individual
Self renewal
What is Symmetric
self-renewal?
Increase stem cell pool – NO generation of differentiated progeny
What is asymmetric self renewal?
Maintain stem cell
pool – generation
of differentiated
progeny
What is Lack of
self-renewal?
Deplete stem cell pool – generation of ONLY differentiated progeny
What is lack of sell renewal?
Maintain stem cell pool – NO differentiated progeny
What is the life span of RBC?
120 days
Give example of myeloids?
Granulocytes (White blood cells)
Erythrocytes (Red blood cells)
Platelets
Give examples of lymphoids?
B-Lymphocytes (White blood cells)
T-lymphocytes (White blood cells)
What stage does haemopoiesis start?
Haemopoiesis starts at day 27 in the aorta gonad mesonephros region,
expands rapidly at day 35, then disappear at day 40
What does the disappearance at day 40 of haemopoiesis correlate with?
This “disappearance” correlates with the migration of these hematopoietic stem cells to the foetal liver, which becomes the subsequent site of haemopoiesis.
What is the function of blood cell?
Oxygen transport
Coagulation
Immune response to infection
Immune response to abnormal cells (senescent, malignant etc)
What is polycythaemia, anaemia and Relative polycythaemia
Reduced red cells = anaemia
Raised red cells = polycythaemia
Relative polycythaemia, when plasma volume is reduced > dehydrated
What is the structure of RBC?
bi- concave discs
Give 3 examples of granulocytes?
Have cytoplasmic granules
Neutrophils
Eosinophils
Basophils
What is the most common white cell in adult blood?
Neutrophils
When do you see increased number of neutrophils?
Increased numbers in presence of infection - neutrophilia
e. g. bacterial infection e. g. inflammation
When do you see decreased numbers of neutrophils (neutropenia)?
e.g. side effect of a drug
Chemotherapy or a variety of drugs as a side effect
Also SLE autoimmune disease that causes neutropenia
How long do neutrophils live for?
Only for a few hours 6-8
When do you see increased number of eosinophilias?
e. g Parasitic infection
e. g. Allergies
What condition do you see increased number of basophils?
Rare
Chronic Myeloid Leukaemia
What are monocytes?
Phagocytic & antigen-presenting cells
When do you see increase number of monocytes?
TB
What are Natural killer cells?
large granular lymphocytes
Recognise “non-self”
Cells, viruses
What is the action of B lymphocytes?
Adaptive immune system
Rearrange the immunoglobulin genes to enable antigen specific antibody production
Provide specific immunoglobins when under a threat
Formed because the specific immunoglobin gene is re ordered so they can be produced by plasma cells
What is the action of T cells?
rearrange the T-cell antigen receptor cell-mediated immunity target specific cytotoxicity Interact with B cells, macrophages Regulate immune responses
What is lymphocytosis?
Increase number of lymphocytes
What can cause lymhocytosis?
Atypical lymphocytes of glandular fever (infectious mononucleosis)
Chronic lymphocytic leukaemia
What is a cause of lymphopenia (reduce numbers)?
Post bone marrow transplant
What can cause plasmacytosis?
Infection
Myeloma
What are plateleets dervived from?
Platelets are derived from bone marrow megakaryocytes
Megakaryocytes fragment to form the platelets
What is the action of platelets?
Together with soluble plasma clotting factors and endothelial cells form part of the blood clotting system
Aggregate to plug holes in damaged blood vessels
What are diagnostic tests for haemotology?
Full Blood Count
Blood Film (or “smear”)
Coagulation Screen
What is tested in full blood count?
Haemoglobin concentration
Red cell parameters
MCV (mean cell volume)
MCH (mean cell Hb)
White Cell Count (WCC)
Platelet Count
What is Coagulation Screen?
Tests measure the time taken for a clot to form when plasma is mixed with specified reagents
What parts of the coagulation cascaed can be assayed in coagulation screen?
Prothrombin Time
Activated Partial Thromboplastin Time
Thrombin Time
From where is bone marrow taken from?
Under local anaesthetic, liquid marrow is aspirated from the
posterior iliac crest of the pelvis
What are the 3 key factors to collecting a blood specimen?
appropriate sample from the patient
collected into EDTA anticoagulated blood
Samples should get to the lab promptly since EDTA artefact can affect the results.
What is the reference range used when doing tests?
the set of values for a given test that incorporates 95% of the normal population
What is sensitivity?
defined as the proportion of abnormal results correctly classified by the test
expresses the ability to detect a true abnormality
What is the formula of sensitivity?
TP / (TP+FN)
What is specificity?
Defined as the proportion of normal results correctly classified by the test
Expresses the ability to exclude an abnormal result in a healthy person
What is the formula of specificity?
TN/ (TN+FP)
When would it be normal to have a abnormal lymphocyte count?
post-splenectomy mild lymphocytosis
3 months post-bone marrow transplant lymphopenia
Give 5 examples of microcytic hypochromic?
Iron deficiency Thalassaemia Anaemia of chronic disease Lead poisonng Sideroblastic anaemia
What is the mean cell volume and mean cell HB of microcytic hypochromic?
MCV
What is the classification of normocytic normochromic?
MCV 80-95 fl & MCH ≥ 27 pg
GIve example of normocytic normochromic?
Many haemolytic anaemias Anaemia of chronic disease (some cases) After acute blood loss Renal disease Mixed deficiencies Bone marrow failure
What is the calssifciation of macrocytic?
MCV >95 fl
Give example of Macrocytic?
Megaloblastic: Vitamin B12 or folate deficiency
Non-megaloblastic: alcohol, liver disease, myelodysplasia, aplastic anaemia etc
What is megloblastic anemia?
Megaloblastic anemia is the results from inhibition of DNA synthesis during red blood cell production
