Physiology of Blood Cells and Haematological Terminology Flashcards
(51 cards)
What are all blood cells ultimate derived from?
multipotent haematopoietic stem cells
What two lineages can this give rise to?
Lymphoid Stem Cells
Myeloid Stem Cells
What cells are derived from the multipotent myeloid precursor?
Megakaryocytes
Granulocyte-Monocyte
Erythroid
What cells are derived from the multipotent lymphoid precursor?
T cells
B cells
NK cells
What are some common features of blasts?
They have a large nucleus and a small amount of cytoplasm
Multipotent haematopoietic stem cells give rise to blasts eg myeloblast
How does the colour of red cells change as they mature?
When they are immature they are more blue/purple
As they mature they become pinker
– blue tinge to cytoplasm– young POLYCHORMASIA
What is EPO used for?Which cells produce EPO? What can trigger the production of EPO?
Erythropoiesis
EPO is mainly produced in the kidneys by the juxtatubular interstitial cells (90%)
10% liver– heaptocyte and interstitial cells
EPO production is stimulated by hypoxia or anaemia
What is the life span of a red blood cell? What is it destroyed by?
120 days
Phagocytic cells of spleen
Define anisocytosis and poikilocytosis
Anisocytosis = red cells show more variation in SIZE than is normal (latin for aniso= uneven) Poikilocytosis = red cells show more variation in SHAPE than is normal (poikilo=variation/uneven)
What can be used as a reference in a blood film to determine whether the red blood cells are microcytic or macrocytic?
Lymphocytes are generally all the same size and are used as a reference.
Normally RBCs are a bit smaller than lymphocytes
Define hypochromia.
The red cells have a larger area of central pallor than normal
NOTE: normal red cells have a central pallor that covers around 1/3 of the red cell diameter
NOTE: hypochromia and microcytosis tend to go together as they are both caused by reduced Hb synthesis
Define hyperchromia.
The red cells lack a central pallor– normal rbc have a pale centre
State two important types of hyperchromatic cells.
Spherocytes
Irregularly Contracted Cells
What is responsible for the round shape of the spherocytes in spherocytosis?
It is caused by a loss of cell membrane that is not accompanied by an equivalent loss of cytoplasm (inadequate attachment between cytoskeleton and membrane)
State a cause of spherocytosis.
Hereditary spherocytosis– but not all the cells are spherical
How do irregularly contracted cells differe in appearance from normal rbc? What usually causes the formation of irregularly contracted cells?
Irregulat in outline, smaller and no central pallor
Oxidant damage
Define polychromasia.
An increased blue tinge to the cytoplasm of a cell– INDICATES CELL IS YOUNG
What can reticulocytes (IMMATURE RBC) be stained with?
Methylene blue
State six different types of poikilocytosis.
Spherocytes Elliptocytes Fragments Irregularly contracted cells Target cells Sickle cells
What are target cells? State some causes of target cells in the blood film.
Target cells have an accumulation of haemoglobin in the middle of the central pallor
It is caused by obstructive jaundice, hyposplenism, liver disease, haemoglobinopathies
State two causes of eliptocytosis.
Hereditary eliptocytosis Iron deficiency (also hypochromic)
What biochemical phenomenon causes the sickling of red blood cells?
Polymerisation of haemoglobin S when present in a high concentration
What is another name for fragments?
Schistocytes
State two different ways in which red blood cells can clump together and describe why they happen.
Rouleaux – like a stack of coins – it is caused by a change in plasma proteins pushing the red cells together
Agglutinates – irregular clumps – caused by antibodies on the cell surface making the cells stick together
