W9 Intro to blood Flashcards
(39 cards)
RBC
AKA Erythrocytes
Biconcave discs
No nucleus and do not contain DNA, RNA or mitochondria (still metabolically glucose by glycolysis)
WBC
AKA leukocytes
Colourless
Neutrophils
Polymorphonuclear
Irregular, multi-lobed nucleus
Granulocyte
prominent cytoplasmic granules
Two other types of granulocyte
Eosinophil (granules stain red w/eosin) = 1-4% of WBC
Granules contain substances that are going to be released from the cell
Basophil (granules stain blue/purple w/basic dyes) = <0.5% of WBC
In basophil can’t see nucleus because of granules
Mononuclear cells
Lack granules Large, regular nuclei Two types: Monocytes Lymphocytes
Platelets (a.k.a. “thrombocytes” )
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
Bone marrow contains many immature cells
Some blood diseases can be treated by bone marrow transplantation
Plasma fluid contains…
Water Salts Proteins Organic molecules e.g. Metabolites Carbohydrates Lipids
Ionic constituents of plasma
Positive ions (cations)
Sodium (Na+)
Also potassium, calcium, magnesium and hydrogen ions
Negative ions (anions)
Chloride (Cl-)
Also bicarbonate, phosphate, sulphate & organic anions
Plasma V serum
Plasma is the fluid component of whole blood
Serum is the fluid left after blood clotting
Some blood tests require unclotted blood
Use anticoagulant e.g. EDTA
Other tests work better with serum than plasma (as proteins removed)
Plasma proteins
Normal: 7-9% of plasma is protein
Complex- thousands of different proteins
But > 90% is a single protein: albumin (or = serum albumin)
Function of blood - transport
Carry oxygen / nutrients to tissues
Remove CO2 / other waste products from tissues
Transport other substances (e.g. hormones) from sites of production sites of action
Erythrocytes - function
Transport oxygen from lungs → body tissues
Help in removal of CO2 from body tissues → lungs:
- Most CO2 carried as bicarbonate in plasma
- Red cell enzyme carbonic anhydrase helps CO2:
- To dissolve in plasma in the tissues (because CO2 doesn’t readily dissolve in water → forms carbonic acid)
- Come out of solution in the lungs
Erythrocytes - major consituent
Major constituent is the protein haemoglobin (Hb)
Hb binds oxygen
Carries it from the lungs to the tissues
Haemoglobin
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
Haem group not prosthetic + extra group carried by protein
Haemoglobin - saturated/unsaturated
Oxyhaemoglobin
Fully saturated with O2 = bright red
Deoxyhaemoglobin
Lost all O2 = dark red
Haemoglobin - binding to ferrous ion
The haem holds a ferrous (Fe2+) iron atom
Oxygen binds reversibly to the iron atom by a coordination bond
Basis of pulse oximetry
Measures the colour of the haemoglobin = measures SATS
Determines if patient is hypoxic
[Hb] in RBC
There are about 300,000,000 Hb molecules in each RBC
Very high concentration
Almost 50% of the space in a red cell is taken up by Hb
Plasma transport
Plasma carries soluble metabolites in solution
Plasma proteins carry substances which are poorly soluble in water e.g.
- lipids
- lipid soluble hormones and vitamins
Plasma proteins also carry metal ions e.g.
Ca2+
Fe2+ (needed for bacterial growth)
Cu2+
All ions above toxic
Plasma transport - examples
Albumin acts as a general purpose carrier
But many substances have a specialised carrier e.g.
Thyroxine binding globulin (TBG) = as thyrohormones not v.water soluble
Transferrin
Transferrin
Binds to ion in blood + carries to tissue
Keeps it away from bacteria
Cells have receptor which binds to transferrin
Ion taken up
WBC function
Neutrophils
Phagocytose and kill bacteria & fungi
Main mediators of innate immunity
Lymphocytes
Main mediators of adaptive (acquired) immunity
Produce antibodies
Kill virus infected cells
Eosinophils - function
Kill parasites
Involved in allergic responses
