Physiology of Blood Cells and Haematological Terminology Flashcards
Outline the stem cell heirarchy
pluritpotent lympphoid-myeloid stem cell ->lymphoid stem cell/ multipotent myeloid stem cell or precursor
lymphoid sc-> t cell/ b cell/ nk cell
myeloid sc-> granulocyte-monocyte/erythroid/magakarocyte
outline normal erythroid maturation
multipotent myeloid sc-> proerythroblast -> early,intermediate and late erythroblats-> erythrocyte
What stmulates erythropoiesis? Where does it occur?
hypoxia/anaemia
90% of erythropoietin from juxtatubular interstitial cells of the kidneys.
10% of erythropoietin from hepatocytes and interstitial cells of the liver
How long do erythrocytes survive?
about 120 days in the blood stream and transport CO2 and O2 -> then destroyed by phagocytes in spleen
outline the normal granulocyte maturation?
multipotent myeloid sc-> myeloblast -> promyelocyte-> myelocyte-> band form -> neutrophil
What is the physiological function of neutrophils?
Neutrophil granulocyte survives 7-10 hours in circulation before migrating to tissues.
Defence against infection - phagocytoses and then kills microorganisms
What is the physiological function of eosinophils?
Spends less time in circulation than neutrophil.
Defence against parasitic infection
also involved in allergic reactions
What is the physiological function of basophils?
allergic responses
What is the physiological function of monocytes?
Spend several days in the circulation.
Phagocytose bacteria, fungi and dead tissue.
Migrate to tissues to become macrophages.
Macrophages store and release iron
What is the physiological function of platelets?
Multipotent haematopoietic stem cell -> megakaryocyte -> platelet.
Survive 10 days in circulation.
Have a role in primary haemostasis in contributing phospholipid to promote blood coagulation
What is the physiological function of lymphocytes?
Lymphoid stem cell gives rise to T, B and NK cells.
Lymphocytes recirculate to lymph nodes and other tissues and then back into the blood stream.
Lifespan intravascular is very variable
What do anisocytosis and poikilocytosis mean?
Anisocytosis – red cells show more variation in size than is normal
Poikilocytosis – more variation in shape than is normal
What do microcytosis and macrocytosis mean?
Microcytosis – red cells smaller than normal.
Macrocytosis – larger than normal.
types of macrocytes :
Round macrocytes.
Oval macrocytes.
Polychromatic macrocytes (darker blue due to ribosomes -> newly synthesized)
What arethe categories of anaemia?
Microcytic – red cells that are smaller than normal or an anaemia with small red cells.
Normocytic – red cells of normal size or an anaemia with normal sized red cells.
Macrocytic – red cells that are larger than normal or an anaemia with large red cells
What is hypochromia?
RBCs that have a large central pallor – less haemoglobin in the cell and thus a flatter cell and less colour
Normal RBCs have one-third a diameter that is pale.
*Often Hypochromia and Microcytosis go hand-in-hand - both caused by reduced haemoglobin