Introduction Flashcards
What is haematology
Study of blood, blood forming organs and blood diseases
what is blood
specialised fluid (technically tissue) composed of cells suspended in liquid plasma
What is the difference between plasma and serum
plasma contains clotting factors
serum does NOT contain clotting factors
what are the main types of blood cells
RBC
WBC
platelets
What is haematopoeisis
production of blood cells
Where does haematopoeisis in the adult occur and by which cells
bone marrow (axial skeleton) pluripotent stem cells
where is the site of haematopoeisis in the embryo
yolk sac
then liver
(spleen additionally)
where is the site of haematopoeisis at birth
bone marrow primarily
liver and spleen when needed
what happens to bone marrow during growth
number of active sites of bone marrow decrease but still retain ability
Function of stem cells
self renewal
proliferation
differentiation
majority sit in a quiescent state
which cell is the first in the haematopoeitic tree
haematopoeitic stem cell HSC
what is a CMP in the haematopoeitic tree
common myeloid precursor
gives rise to RBC, platelets, granulocytes, macrophages
what is a CLP in the haematopoeitic tree
common lymphoid precursor
gives rise to T cell, B cell and NK cell
what happens to the cells through granulopoeisis
cells get smaller
what is erythropoeisis and where does it occur
RBC production
bone marrow
what happens to the nuclei of the cells as they progress through erythropoeisis
nuclei get smaller and eventually vanish
when a red cell just enters the bloodstream from the bone marrow, what is it called
reticulocyte
what is a reticulocyte
immature RBC
hangs around in blood for 2-3 days before turning into a mature red cell
reticulocytes contain RNA, true or false
TRUE
erythrocytes/mature red cells contain RNA, true or false
FALSE
What is the precursor cell for platelets
megakaryocytes
what is unique about megakaryocytes
they are big cells that undergo nuclei divisions but not cytoplasm divisions
how do megakaryocytes form platelets
parts of the cytoplasm bud off to form platelets
immature megakaryocytes have fewer/more nuclei than mature ones
fewer
what are granulocytes
give examples
contain granules that can be seen with staining under light microscopy
neutrophils, eosinophils, basophils
how do neutrophils stain
neutrally - mixed, bit of both
describe the appearance of a neutrophil
segmented nucleus (multi-lobed) aka polymorph
describe the function of a neutrophil
circulates in the blood ~8-10 hours
enters tissue to flag up inflammation and fight acute infection
phagocytosis
create pus and cause liquefaction
give causes of neutrophilia
infection
trauma
infarction
corticosteroids
why do corticosteroids cause neutrophilia
they impair their ability to bind to the endothelium and cross over, so instead of being found at the margin, neutrophils are found in the centre of the vessel
how do eosinophils stain
bright orange / red
describe the appearance of an eosinophil
bi-lobed nucleus with a bright red cytoplasm
function of an eosinophil
fights parasitic infection
involved in hypersensitivity and atopy - asthma, eczema, hayfever
how do basophils stain
dark purple
appearance of a basophil
dark purple cytoplasm which obscures appearance of the nucleus
function of a basophil
similar to mast cells
granules contain histamine
Describe appearance of a monocyte
1 large nucleus that is NOT dense
blue cytoplasm
function of monocyte
circulates in blood for 1 week
enters tissue to become macrophage (or equivalent)
phagocytosis and antigen presenting to lymphocytes
attract other cells
neutrophils are more long lived than macrophages, true or false
false
where are these cells found:
Kupffer
Microglia
Langerhans
Liver
CNS
Skin
how can lymphocytes be classified according to appearance
mature
activated / atypical
describe the appearance of a mature lymphocyte
small
condensed nucleus with a rim of cytoplasm
describe the appearance of an activated/atypical lymphocyte
large
more open nucleus
plentiful blue cytoplasm
what does the presence of an activated lymphocyte suggest?
viral infection eg EBV, HIV, viral hepatitis
what can lymphocytes differentiate into
T cells
B cells
NK cells
what are the types of T cells and their function
CD4+ T cell: helps B cells turn into plasma cells
activate CD8+ cells and macrophages
CD8+ T cell: destroy infected/tumour cells
CD4+ is activated by MHC 1/2
CD8+ is activated by MHC 1/2
CD4+ - MHC II
CD8+ - MHC I
how can you identify primitive precursors in the haematopoeitic tree
immunophenotyping - identifying proteins on cell surface
bio-assays - growing cells in culture to identify lineage
where can you take a bone marrow aspiration from
posterior iliac crests (preferred)
sternum
what is a trephine biopsy
core biopsy of bone marrow which allows you to see bone marrow in situ
