Histology Flashcards
what is haemopoeisis
production of blood cells
what are blood cells derived from
pluripotent stem cells
where is the sites of haematopoiesis at different ages
Embryo
- yolk sac then liver then spleen
Birth
- bone marrow mostly
- liver and spleen when needed
Birth to Maturity
- number of active sites in bone marrow decreases but retain ability for haematopoiesis
Adult
- bone marrow of skull, ribs sternum, pelvis, proximal ends of femur
in general, what are the sub-headings for division to a mature cell in the haemopoietic tree
Stem Cells»_space; Multipoint progenitors»_space; Oligolineage progenitors»_space; Mature cells
what are the two Oligolineage progenitors
CMP = common myeloid progenitor
CLP = common lymphocyte progenitor
what is the progression of precursor to mature cell for neutrophils
myeloblast to promyelocyte to myelocyte through metamyelocyte forms eventually neutrophils
what is erythropoiesis
red blood cell production
what is the progression of precursor to mature cell for RBC/erythrocyte
1 - Pronormoblast 2 - Basophilic/early normoblast 3 - Polychromatophilic/ intermediate normoblast 4 - Orthochromatic/late normoblast 5 - Reticulocyte 6 - Mature red cell/erythrocyte
what happens during the different stages/cells of erythropoiesis
- size drops as cell matures
- once they have the haemoglobin in the cell they start oxygen carrying
- reticulocytes are first cell to be seen in blood stream
- all previous are in the bone marrow
what in the blood stream can show how active the bone marrow is
number of reticulocytes
what key step occurs between the Orthochromatic/late normoblast and reticulocyte
lose nucleus and RNA
how does a reticulocyte and a RBC differ in appear
reticulocyte stains slightly blue due to left over RNA still present
what is the precursor cell for platelets
megakaryocyte
what are the functions of the blood cells
Red cells
- Carry oxygen
Platelets
- Stop bleeding
White cells
- Fight infection
what are the different types of white cells
granulocytes
macrophages
what are granulocytes names the way they are
they contain granules
named according to their uptake of stains
what are the 3 types of granulocytes
Eosinophils (red)
Basophils (blue-black)
Neutrophils (didn’t take up either of the colour dyes strongly i.e. neutral)
what are graunlocytes derived from
GMP
what is the structure of neutrophils
Segmented nucleus (polymorph) Neutral staining granules
what is the function of neutrophils
Short life in circulation – transit to tissues.
Phagocytose invaders
Kill with granule contents and die in the process
Attract other cells
Increased by body stress – infection, trauma, infarction
what is the structure of eosinophils
Usually bi-lobed
Bright orange/red granules
what is the function of eosinophils
Fight parasitic infections
Involved in hypersensitivity (allergic reactions)
Often elevated in patients with allergic conditions (e.g. asthma, atopic rhinitis)
what is the structure of basophils
Infrequent in circulation
Large deep purple granules obscuring nucleus
what is the function of basophils
Circulating version of tissue mast cell
Mediates hypersensitivity reactions
FcReceptors bind IgE
Granules contain histamine
what are monocytes precursors of
macrophages
what is the structure of monocytes
Large single nucleus
what is the function of monocytes
Circulate for a week and enter tissues to become macrophages
Phagocyose invaders
- Kill them/endocytose
- Present antigen to lymphocytes
Attract other cells
More long lived than neutrophils
what is the structure of lymphocytes
small with condensed nucleus and rim of cytoplasm
activated/atypical node = large with plentiful blue cytoplasm and the nucleus has a more “open” structure
what investigations can be done to assess the primitive precursors
Immunophenotyping
- Expression profile of proteins (antigens) on the surface of cells
Bio-assays
- Culture in vitro and show lineage of progeny in different growth conditions
where is a common site for bone marrow biopsies because it is quite active
posterior iliac crests
what are causes of neutrophilia
bacterial infection inflammation e.g. RA trauma/post op corticosteroids myeloproliferative disease
what are causes of lymphocytosis
viral infection
pertussis
childhood response to infection
CLL [smear cells]
