FOUND-SOM-HAEM Flashcards
what are the 3 components of blood and their % makeup?
- plasma-55%
- (buffy coat) WBCs and platelets <1%
- RBCs 45%
what are the components of plasma?
>95% water 6-8% dissolved proteins glucose electrolytes -hormones -co2
what is the difference between plasma and serum?
If you take the clotting factors out of plasma, then you have serum. This occurs in blood centrifugation
describe embryonic stem cell differentiation related to haematopoiesis?
Blastocyte—>pluripotent cells (stem)—->endoderm/germ cells/mesoderm——>forms precursor cells-haemangioblasts
what do haemangioblasts form?
vascular cells
blood cells
what are the sites of fetal haematopoiesis?
- yolk sac
- liver
- spleen
what are the sites of postnatal haematopoiesis?
- —>red bone marrow
- pelvis
- vertebral column
- —>extramedullary regions: thymus
what is haematopoesis?
differentiation of cells to form different blood cells
how many blood cells does each haematopoetic stem cell have the potential to produce after 20 divisions?
10^6
what is the significance of RBCs being anucleate?
no transcription of unnecessary genes
what is the role of RBCs?
-carry O2 from the lungs and return CO2
what is the shape of RBCs and what is it significance?
discoid shape
-increases SA allowing gas exchange to take place over largest possible SA
what are the main functions of thrombocytes (platelets)?
- form platelet plug in order to stop bleeding following injury
- initiates wound healing/ innate immune function
what are the blood cells associated with adaptive immunity?
- all lymphocytes
- B cell
- CD4+ T-cell (Helper)
- CD8+ T-cell (killer)
what is the site of maturation of B-cells ?
bone marrow but once mature, resides in the blood stream and lymph nodes
What is the site of maturation of CD4+/ CD8+ T-cells?
thymus-but once mature, reside in lymph nodes
what are the functions of B-cells?
- primary cell type of humoral immunity
- will differentiate into antibody-producing plasma cells
- also use CD4+ cells to help produce antibodies which are complimentary to the antigen
what are the functions of CD4+ T-cell?
- work with MHC Class II molecules to exogenously process pathogens, and then present the antigens to B-cells
- this causes B cells to produces antibodies complimentary to antigen
what is the role of CD8+ T cells?
work with MHC Class I molecules to endogenously process pathogens-killing them
Which 7 blood cells are associated with innate immunity?
- macrophage
- dendritic cells
- natural killer cells
- mast cells
- neutrophils
- basophils
- eosinophil
which blood cells, associated with innate immune system, are granulocytes?
- mast cells
- basophils
- neutrophils
- eosinophil
which blood cells associated with innate immune system are phagocytes, sentinel and APC?
- macrophage
- dendritic cells
what type of cell are natural killer cells?
lymphocytes
what is the appearance of macrophages?
central round nucleus with a vacuole
what is the appearance of dendritic cells?
large branchlike projections coming off the body
what is the appearance of natural killer cells?
- single-lobed nucleus
- very little cytoplasm
what is the appearance of mast cells?
- ‘fried egg’ appearance of nucleus and cytoplasm
- granules
what is the appearance of neutrophils?
- multilobed nucleus
- granules
what is the appearance of basophils?
- 2-lobed nucleus
- purple-staining
- granules
what is the appearance of eosinophils?
- 2-lobed nucleus
- orange-staining
- granules
what does a monocyte develop into?
macrophage
what is the shape of the nucleus of monocytes?
horse-shoe shaped
what are the roles of macrophages?
- phagocytose pathogens
- may present the digested antibodies to stimulate the rest of the immune system
what are the roles of dendritic cells?
- phagocytose pathogens
- presents digested antibodies to trigger adaptive immune response
what is the role of natural killer cells?
-kills tumour and virus infected cells by releasing perforin
what are the roles of mast cells?
- causes vasodilation and inflammation
- degranulation to release heparin and histamines
- can phagocytose and present antigens too
what are the most abundant granulocyte cells?
neutrophils (70%)
what are the roles of neutrophils?
first responder at the site of infection
- degranulates releasing toxins which kill pathogens
- can also phagocytose
what are the roles of basophils?
- defends against parasites
- causes allergic inflammation by degranulation to release histamine and heparin
what are the roles of eosinophils?
- defends against parasites
- causes allergic inflammation by degranulation to release histamine and heparin
how does cell differentiation of blood cells occur?
- gene expression
- cellular environment
- cellular signalling from transcription/ growth factors
how are erythropoietins (EPO) produced?
produced by interstitial fibroblasts of the juxtaglomerular apparatus in the kidney
what do EPOs do?
stimulate production of RBCs
where are thrombopoietin (TPOs) produced?
in the liver
what is the function of TPOs?
aids production of platelets
how are granulocyte-colony stimulating factor (G-CSF) produced?
produced by macrophages and endothelial cells
what is the role of G-CSF?
stimulates production and maturation of neutrophils
what are interleukins?
proteins that mediate communication between cells
which cell type is most involved in the cutaneous immunosurveillance?
-langerhans cells
which transcription factor is involved in the production of neutrophils?
G-CSF
which WBC type bridges innate and adaptive immunity?
monocytes-as they can engulf and destroy foreign organisms and particles through phagocytosis (innate) and then stimulate T and B cells through presentation of digested peptides on their cell surface (adaptive)
describe the basic structure of immunoglobulin molecule
- heavy and light chains encoded by different genes
- constant region functions to bind specific receptors Fc receptors
- variable region functions to bind antigen
what are the 5 types of immunoglobulins?
- IgM
- IgG
- IgA
- IgE
- IgD
which immunoglobulins are involved in innate immune cell activation?
IgA
IgE
what are the roles of IgG?
- opsonisation
- activation of complement
- immune cell activation
what is the role of IgM?
activation of serum complement
which cytokines are important for adaptive immunity?
- IFN-induces IgG class switch and promotes development of effector CD8+ T cells
- IL4/ IL21-induces IgG class switch, aids affinity maturation of B cells for production of plasma and memory cells
- IL17-involved in mucosal immunity
- IL10-immune response inhibition
describe B-cell maturation.
- germinal cell reaction
- B cells enter LN to encounter antigen and cognate help from CD4+ T-cells
- affinity maturation occurs to enhance antibody-antigen interaction
- generation of immune memory
- -memory B cells
- -plasma cells
what is the role of mature RBCs?
o2 transportation
in which process are RBCs synthesised?
erythropoiesis
what are the steps involved in erythropoiesis?
IN BONE MARROW:
stem cell—->proerythroblast—->early erythroblast (ribosome synthesis)—->late erythroblast (Hb acculmulation)—->normoblast——>reticulocyte (remains in BM for 3 days)
CIRCULATION:
reticulocyte—–(24-48hrs)—->erythrocyte
what is the average lifespan of an erythrocyte?
120 days
which 3 organs are involved in erythrocyte removal?
- spleen
- liver
- bone marrow
which cells are involved in erythrocyte removal?
macrophages
describe how macrophages remove erythrocytes.
- macrophages engulf and break down old RBCs
- left with lots of Hb
- Hb broken down into globin and haem
- globulin broken down into amino acids
- haem broken down into Fe2+ and bilirubin
what are the amino acids from globin used for?
used in haematopoiesis in bone marrow
what are the Fe2+ ions from haem used for?
- obtains a Fe2+ transporter-transferin in liver
- travels to bone marrow for erythropoiesis
what happens to the bilirubin from haem?
-enters bile
-secreted into duodeum via the bile duct
-excreted in faeces
OR
-reabsorbed and excreted in urine
what hormone is important in influencing erythropoiesis and what does it do?
erythropoietin-stimulates erythropoietin
which organ secretes hormone erythropoietin?
kidney
what is a potential consequence of kidney failure due to its resulting inability to secrete erythropoetin?
anemia
