Haematology 1 Flashcards
Where do blood cells originate from and what 2 things do they give rise to
Multipotent haemopoietic stem cells in the bone marrow
Myeloid stem cell/precursor
Lymphoid stem cell
What can a lymphoid stem cell give rise to
NK cell
B cell
T cell
What can a myeloid stem cell give rise to
Proerythroblast
Granulocyte
Erythroid
Megakaryocyte
What feature are stem cells characterised by and how is it achieved
Ability to self renew and produce mature progeny
They can divide into two cells with different characteristics, one another stem cell and the other a cell capable of differentiating to mature progeny
Describe the how a stem cell gives rise to a red cell
- Multipotent haemopoietic stem cells
- Myeloid stem cell precursor
- Proerythroblast
- Erythroblasts
- erythrocytes
What is erythropoiesis and what does it require
Production of red cells Requires erythropoietin (synthesised by the kidney)
Describe the red cell response to hypoxia
- Hypoxia/anaemia
- Erythropoietin synthesis
- Increased bone marrow activity
- Increased red cell production
Where does erythropoietin synthesis occur (+proportion)
Liver hepatocytes and interstitial cells - 10%
Kidney juxtatubular interstitial cell - 90%
Describe the red blood cell (lifespan, functions and excretion/removal)
Survives 120 days in the blood stream
Function is oxygen and CO2 transport
Destroyed phagocytic cells of the spleen
Describe the physiology of white cells from stem cells
- Multipotent haemopoietic stem cell
- Myeloblast + monoblast
- Granulocytes + monocytes
Describe neutrophils
Defence against infections via phagocytosis
Neutrophil granulocytes survive 7-10 hours in the circulation before migrating to tissues
Describe eosinophils (role+circulatory lifespan)
Defence against parasitic infection
Shorter duration in the circulation than the neutrophil
What is the role of basophils
Allergic response
Describe monocytes
Migrate to tissues where they develop into macrophages - phagocytic and scavenging function
Stores and releases iron
Stays in the circulation for several days
Describe platelets
Primary haemostasis
Contribute phospholipid - promotes blood coagulation
Derived from megakaryocytic
Survive 10 days in circulation
Describe lymphocytes
Lymphoid stem cells -> T, B, NK cells
Lymphocytes recirculate to lymph nodes and other tissues then back to the blood
Variable intravascular lifespan
What is anisocytosis
Red cells show more variation in size than is normal
What is poikilocytosis
Red cells show more variation in shape than is normal
What is microcytosis
Red cells are smaller than normal
microcyte = cell that is smaller
What is macrocytosis
Red cells are larger than normal
macrocyte = cell that is larger
What are the types of macrocytes
Round macrocytes
Oval macrocytes
Polychromatic macrocytes
Describe the colour differences in a normal red cell
1/3 of the diameter of red cells are pale
Due to the disk shape of the cell the centre has less haemoglobin
What is hypochromia
Red cells have a larger area of central pallor than normal
Due to a lower haemoglobin content and conc. + flatter cell
Often associated with microcytosis
What is hyperchromia
Cells lack central pallor
Due to greater thickness or abnormal shape
2 types: spherocytes and irregularly contracted cells
Describe spherocytes
Cells that are approx. spherical
Round, regular outline and lack central pallor
Due to loss of cell membrane without the loss of an equivalent amount of cytoplasm -> round cell
Describe irregularly contracted cells
Irregular outline but smaller than normal cells + no central pallor
Due to oxidant damage to the cell membrane and to the haemoglobin
What is polychromasia
Increased blue tinge to the cytoplasm of a red cell
Indicates that the red cell is young
How can you tell which red cells are young
Look for polychromasia
Reticulocyte stain - exposes red cells to new methylene blue, precipitates as a network of reticulum
What are the shapes that poikilocytes can come in
Spherocytes Irregularly contracted cells Sickle cells Target cells Elliptocytes q Fragments
Describe target cells
Cells with an accumulation of haemoglobin in the centre of the area of central pallor
Occurs in obstructive jaundice, liver disease, haemoglobinopathies and hyposplenism
Describe elliptocytes
Elliptical in shape
Occurs in hereditary elliptocytosis and in iron deficiency
Describe sickle cells
Sickle or crescent shaped
Results from the polymerisation of haemoglobin S when it is present in a high concentration
Describe fragments
AKA schistocytes
Small pieces of red cells
Indicates that a red cell has fragmented
Describe rouleaux
Stacks of red cells
Resembles a pile of coins
Results from alterations in plasma proteins
What are agglutinates
Similar to rouleaux but are irregular clumps
Results from antibodies on the surface of the cells
What is a Howell-Jolly body
Nuclear remnant in a red cell
Commonest cause is lack of splenic function
Define: Leucocytosis Leucopenia Neutrophilia Neutropenia Lymphocytosis Eosniphilia
Leucocytosis - too many white cells Leucopenia - too few white cells Neutrophilia - too many neutrophils Neutropenia - too few neutrophils Lymphocytosis - too many lymphocytes Eosniphilia - too many eosinophils
Define: Thrombocytosis Thrombocytopenia Erythrocytosis Reticulocytosis Lymphopenia
Thrombocytosis - too many Thrombocytopenia Erythrocytosis Reticulocytosis Lymphopenia
What does atypical lymphocyte describe
Abnormal cells present in infectious mononucleosis (glandular fever)
What is left shift
Increase in non-segmented neutrophils or neutrophil precursors present in the blood
What is toxic granulation
Heavy granulation of neutrophils
Results from infection, inflammation and tissue necrosis
Normal feature of pregnancy
Describe the hypersegmented neutrophil
Increase in the average number of neutrophil lobes or segments
Results from a lack of vitamin B12 or folic acid
Right shift
What is required for differentiation of multipotent haemopoietic stem cells into granulocytes/monocytes
Cytokines (G-CSF, M-CSF, GM-CSF)
interleukins are required
