Theme 7 Haematology: Introduction to Haematology Flashcards
What is haemopoiesis?
the production of blood cells and platelets, which occurs in the bone marrow
What are the properties of haemopoietic stem cells?
- self renewal (stem cells dividing to make more stem cells)
- high proliferative potential
- differential potential for all lineages
- long term activity throughout the lifespan of the individuals
In symmetrical self-renewal, are the daughter cells identical to parent cells?
yes
what day does haemopoiesis start in embryonic development ?
starts at day 27
Explain the different sites that haemopoisis occurs during embryonic development?
- Starts in AGM (aorto-gonado-mesonephros)
- haemopoietic stem cells migrate to the foetal liver
- Then spleen and bone marrow
Where are the sites of haemopoiesis in early life?
liver and spleen
Explain the haemopoietic lineages e.g what can a stem cell go onto become?
Can either become:
- Myeloid precursor
- granulocytes (WBCs) –> neutrophils, monocyte, eosinophil, basophil
- erythrocytes (RBCs)
- platelets - Lymphoid
- B-lymphocytes (WBCs)
- T-lymphocytes (WBCs)
What are the functions of blood cells?
- oxygen transport (they contain haemoglobin)
- coagulation (haemostasis)
- immune response to infection
- immune response to abnormal cells
What is the lifespan of a red blood cell?
120 days
What is:
- Anaemia
- Polycythaemia
- Reduced red cells
2. Raised red cells
What are the 3 classifications of white blood cells?
- Granulocytes
- neutrophils
- eosinophils
- basophils - Monocytes
- Lymphocytes
- T cells
- B cells
- NK cells
What is the most common white cell in adult blood?
neutrophils
What is:
- neutrophilia
- neutropenia
- increased numbers of neutrophils
2. decreased numbers of neutrophils
What is eosinophilia
increased number of eosinophils e.g parasitic infections, allergies
What is basophilia?
increased number of basophils –> this is a hall mark of chronic myeloid leukaemia
What is monocytosis?
increased numbers of monocytes e.g tuberculosis
When monocytes migrate to tissues, what are they called?
macrophages
What is:
- Lymphocytosis
- Lymphopenia
- increased numbers of lymphocytes e.g in glandular fever
2. decreased numbers of lymphocytes e.g post bone marrow transplant
Which immune system are B and T lymphocytes apart of?
adaptive immune system
What is plasmacytosis?
increased number of plasma cells e.g in infection, myeloma
Which cells are platelets derived from?
bone marrow megakaryocytes
What does ‘reference range’ mean?
the set of values for a given test that incorporates 95% of the normal population
What does a false negative mean?
a diseased patients with a result in the normal reference range
What does a false positive mean?
a healthy patient with a result outside the normal reference range
What is sensitivity?
- defined as the proportion of abnormal results correctly classified by the test
- expresses the ability to correctly identify those WITH the diesease
How do we calculate the sensitivity of a test?
sensitivity = true positive / (true positive + false negative)
What is specificity?
- the proportion of normal results correctly classified by the test
- expresses the ability to correctly identify those WITHOUT the disease
How do we calculate specificity?
= true negative / (true negative + false positive)
What is microcytic hypochromic anaemia?
small and pale red blood cells
What are the causes of microcytic hypochromic anaemia?
- iron deficiency
- thalassaemia
- anaemia of chronic disease
- lead poisoning
- sideroblastic anaemia
What is normocytic normochromic anaemia?
normal size and haemoglobin content
What is macrocytic anaemia and what are the causes?
- big RBCs
- megaloblastic: VitB12 or folate deficiency
- non-megalobastic: alcohol, liver disease, aplastic anaemia
What is a coagulation screen?
Measures:
- time taken for a clot to form when plasma is mixed with specified re agents
- prothrombin time
- thrombin time
What is a bone marrow aspirate?
under local anaesthetic, liquid marrow is aspirated from the posterior iliac crest of the pelvis and a threphine core biopsy is then taken with a hollow needle
What is the hallmark of iron deficiency anaemia?
- long thin cells called pencil cells
- small, pale red cells (low MCV and MCH)
