Haematology Flashcards
Outline some features present in blood
- Many RBC
- Few WBC
- Platelets
- Plasma- water electrolytes (K+), glucose, lipids, metabolites, gases, hormones, drugs, plasma proteins albumins (transport and colonial osmotic pressure allowing fluid to be sucked back into capillary at venous side), globulins (transport, clotting, precursors to hormones- angiotensinogen so help regulate blood pressure, defence), fibrinogen (clotting)
Outline difference between plasma and serum
- Serum- coagulated blood so no clotting factors- expose to foreign surface
Plasma- uncoagulated blood- often need to add anticoagulation factors: watery substance with many other factors
Outline key facts on RBC
discoid (large SA: volume) 8 micrometres in diameter No nucleus Haemoglobin for O2 and CO2 transport 120 day lifespan
Can RBC be a good measure of glucose intake over last 3 months
Hb1Ac- glycosylated haemoglobin- value increases with more glucose as proteins becomes glycosylated- therefore good measure of glucose intake in last 3 months
can be measures in a blood test
Outline some key WBC
- Neutrophils (60-70%)
- Eosinophils- parasite (worm/ helmet) killing and inflammation (allergic asthma)
- Basophils- release histamine in hypersensitivity reactions
- Monocytes- phagocytic- leave blood to be come macrophages
Lymphocytes- produce antibodies
Explain groupings of cells into phagocytes and immunocytes
Phagocytes- granulocytes (neutrophils, eosinophils, basophils) and monocytes
Immunocytes- lymphocytes
Explain appearance and significance of platelets/ thrombocytes
- Cellular fragments
- Non-nucleated
- Fragments stick together–> Clot formation
- Gives rise to many forms of strokes
Explain where blood clots are formed (haematopoiesis)
- Foetus+ neonate- liver and spleen
- Neonate+child+adult- bone marrow
Explain name of some myeloid and lymphoid stem cells
- Myeloid stem cells form megakaryocytes -> platelets, RBC, Granulocytes (eosinophils, basophils, neutrophils), monocytes
Lymphoid stem cells- B and T lymphocytes
name of regulator of platelet levels and why this has to be controlled so tightly
Thrombopoietin- glycoprotein: produced by liver and kidney
- tightly regulates platelet level
- Thrombosis- clotting can occur if too high no. platelets
- Bleeding- if platelet levels too low
Name of regulator of RBC levels and why this gas to be controlled so tightly
EPO- erythropoietin- natural hormone produced by the kidney
- juxtaglomerular cell in kidney: sense O2 levels too low (hypoxia)
- kidney produces EPO
goes to the bone marrow- so more RBC produced
How do we control WBC production
- Interleukins- type of cytokine controlling proliferation of other WBC
- Colony- stimulating factors (CSF)- stimulated by infections and released by endothelial and other cells
e.g. ‘granulocyte CSF- stimulate neutrophil cell line
Cytotoxic anti-cancer chemotherapy can lead to the destruction of bone marrow cells (as fast growing)- hence often treat with CSF in between 21 day cycle of treatments to help recovery of WBC - However, can in leukaemia (myeloid proliferation)- can lead to greater production of abnormal cells
Explain different ways of recognising no/ amounts of RBS within the blood and why this is clinically important
- Cells per volume- counted by machine or manually per 1L of blood
(used to count RBC or neutrophils) - Haematocrit- centrifuge cells down and see % of RBC (about 45%)
- Haemoglobin- amount (g) per L
- Used to recognise anaemias
How do you work out the mean corpuscular volume of an individual RBC? What does this figure mean?
haematocrit (as decimal)/ no. of RBC per L
This tells you the size of each cell, and is measured in fl
Where each fl is 10^-15
How can the MCV be used to identify certain diseases
- Microcytic anaemia: if patient has anaemia and RBC too small- consistent with deficiency in iron
- Macrocytic anaemia: too large RBC
- If not anaemic but RBC too large- can indicate that patient drunk too much alcohol in last 3 months
Be aware of following terms found on full blood count (FBC)
- Haemoglobin
- WBC
- Platelets
- MCV
- MCH
- RBC
- HCT
- MPV
- haemoglobin
- White blood cells
- Platelets
- MCV= mean corpuscular volume (size of RBC)
- MCH= mean cell haemoglobin (average mass of haemoglobin per RBC in blood) bigger cells tend to have more haemoglobin so related to MCV
- RBC
- HCT- haematocrit test- % RBC
- MPV- mean platelet volume (average size of platelets calculated)
What does -philia, -penia, and -cytosis mean
e.g. pancytopenia- what does this mean and what can cause this
- philia/ -cytosis- increased cell count
- penia- decreased cell count
- Pancytopenia= reduction in all cell counts due to anti-cancer chemotherapy
Briefly explain what high/ low amounts of platelets, leukocytes, neutrophils, eosinophils, monocytes and lymphocytes can mean
- Platelets- thrombocytosis (increased thrombosis/ clotting risk) or thrombocytopenia (caused as side effect drugs or idiopathic- no idea!)
- Leucocytes- leucocytosis or leukopenia
- Neutrophils- neutrophilia (caused by bacterial/ fungal infection, trauma or inflammation) or neutropenia (infection- viral or drugs)
- Eosinophils- eosinophilia (allergy/ atopy associated with hay fever, asthma and eczema)
- Monocytes (monocytosis- due to infection can be chronic e.g. TB)
- Lymphocytes- Lymphocytosis (infection- bacterial/ viral or lymphoma- cancer lymphoid tissue) or lymphopenia (inflammation, lymphoma- again can increase or decrease no. lymphocytes or steroids)
Explain some important markers of infection
Change in temperature
Delirium in older individuals
Neutrophilia
C reactive protein (released from the liver upon infection)
Outline different blood groups
Over 400 blood groups yet ABO and rhesus are clinically important ones
ABO blood groups
REM: A has a antigens present on RBC so will produce B antibodies if foreign B antigen present
B- opposite
AB- both A and B antigens so no antibodies
O- has no A or B antigens o both antibodies
Rhesus
Important rhesus D antigen (RhD)
Referred to as +ve or -ve
If +ve D antigens present so no D antibodies
If in doubt O -ve- has A, B or D antigens so lack of immune response
Why is it important to test if rhesus D +ve or -ve in pregnancy
- Vast majority (85%) rhesus +ve
If mother rhesus -ve, statistically likely that foetus rhesus +ve as likely that father rhesus +ve- Not a problem in first birth as no mix of foetal/ maternal blood until pregnancy
- After birth or miscarriage foetal blood from placenta mixes with maternal blood so produces D antibodies
- Affects 2nd pregnancy as haemolytic disease of new-born
- Therefore given anti- D immunoglobulin- Mop up any D-antigens that get into maternal blood and prevent production of D- antibodies
Obstetricians much cleverer than this and monitor if mother rhesus -ve even during 1st pregnancy
