introduction to structure and function of blood Flashcards
structure of blood
Plasma
Red cells
White cells
Platelets
Info on red blood cells (RBC)
they are biconcave discs
have NO nucleus (enucleated)
don’t contain DNA, RNA or mitochondria
(erythrocytes)
Info on WBC
are colourless the 2 most common types - Neutrophils : polymorphonuclear granulocyte - Lymphocytes (leukocytes)
3 types of granulocytes
neutrophil: most common white blood cell (weakly staining granules)
eosinophil : 1-4% of WBC (granules stain red with eosin)
basophil: <0.5% of WBC (granules stain blue/ purple with basic dyes)
what are granulocytes?
A granulocyte is a type of white blood cell that has granules which contain enzymes that are released during infections, allergic reactions and asthma
info on mononuclear cells
lack granules have large and regular nuclei there are 2 main types - Monocytes (largest type of WBC) - Lymphocytes
info on platelets
cytoplasmic fragments
no nucleus
membrane bound
contain granules
where do blood cells come from?
mature blood cells are produced from stem cells in the bone marrow
info on plasma
it is a fluid that contains ... water salts proteins organic molecules (metabolites, carbohydrates, lipids)
ionic constituents of plasma
positive ions
- sodium
- potassium
- calcium
- magnesium
- hydrogen ions
negative ions
- chloride
- bicarbonate
- phosphate
- sulphate
- organic anions
plasma vs serum
plasma is the fluid component of blood
serum is the fluid left after blood clotting - without the clotting factors
plasma proteins
normal 7-9% of plasma protein
complex - thousands of different proteins
90% is albumin
functions of blood
- transport
- defense
- homeostasis
info on transport of the blood
- carry oxygen/ nutrients to tissues
- removes CO2 / other waste products from tissues
- transport other substances (e.g. hormones) from sites of production
erythrocytes
transports oxygen from lungs to the body tissues
helps in the removal of CO2 from body tissues to the lungs
removal of CO2 from body tissues
- most CO2 is carried as bicarbonate in plasma
- red cell enzyme carbonic anhydrase helps CO2
- to dissolve in plasma in the tissues
- come out of solution in the lungs
structure of RBC
average life span ~ 120 days
diameter ~ 8 um
thickness ~ 2 um
info on RBC
- major constituent is the protein
- Hb binds oxygen
- Carries it from the lungs to the tissues
info on haemoglobin
- is a protein tetramer made up of 4 polypeptide chains
(2 alpha globin chains, 2 beta globin chains) - each globin chain carries a haem molecule
- The haem holds a ferroud iron atom
- oxygen binds reversibly to the iron atom
info on haemoglobin (oxygen)
oxyhaemoglobin is fully saturated with O2 making it bright red
deoxyhaemoglobin has lost all O2 therefore it is dark red
pulse oximetry
a method to measure the oxygen saturation within the blood by measuring the colour of haemoglobin
- this can help to determine if a patient is hypoxic
info on transport (plasma proteins)
plasma proteins carry substances which are poorly soluble in water (lipids, lipid soluble hormones and vitamins)
plasma proteins also carry metal ions eg Ca2+, Fe2+, Cu2+
function of WBC
defence
- immunity
WBC and plasma proteins
- clotting (haemostasis)
(platlets and plasma proteins)
types of WBC
neutrophil eosinophil monocyte lymphocyte basophils
neutrophils
phagocytose and kill bacteria & fungi
main mediators of innate immunity
lymphocytes
main mediators of adaptive immunity
produce antibodies kill virus infected cells
eosinophils
kill parasites
involved in allergic responses
basophils
kill parasites
involved in allergic responses
involved in inflammation
monocytes (macrophages)
phagocytosis of dead cells and pathogens
