Lecture 2 - Introduction to structure and function of blood Flashcards
RBCs (6)
Erythrocytes Biconcave discs No nucleus, no DNA Life span - 120 days Diameter - 8 um Thickness - 2um
Erythema
Reddening of the skin
Where do blood cells come from? (3)
- 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 (7)
• Fluid containing o Water o Salts o Proteins o Organic molecules Metabolites Carbohydrates Lipids
Plasma - Ionic constituents (2)
• Positive ions (cations)
Sodium (Na+) / Potassium (K+) / Calcium (Ca2+) / Magnesium (Mg2+) / Hydrogen ions (H+).
• Negative ions (anions)
Chloride (Cl-) / Bicarbonate (HCO3-) / Phosphate (PO43-) / Sulphate (SO42-) / Organic anions.
Plasma and serum (4)
• 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 - Ethylenediaminetetraacetic acid (C10H16N2O8).
• Other tests work better with serum than plasma.
• Purple top – EDTA anticoagulant to stop the blood from clotting.
• Red top – uncoagulated blood.
•
Plasma proteins (4)
- Normal: 7-9% of plasma is protein.
- Complex- thousands of different proteins.
- But > 90% is a single protein: albumin.
- Human serum albumin is the serum albumin found in human blood. It is the most abundant protein in human blood plasma; itconstitutes about half of serum protein. It is produced in the liver.
Functions of blood (3)
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
Defence
Homeostasis
• Keeping the internal environment of the body constant.
Functions of blood - Transport (6,4)
O2 from lungs to body tissues.
Removal of CO2 from body tissues to lungs.
Most CO2 carried as bicarbonate in the plasma.
Carbonic anhydrase - dissolve in plasma in the tissues - come out of solution in the lungs - in RBCs high level of enzyme.
CO2 + H20 –> H2CO3 –> H+ + HCO3-.
Part 3 the -ve charged HCO3- leaves RBC and enters the cytoplasma via diffusion, Cl- ions enter cell (chloride shift, maintains steep concentration gradient. CO3 from respiring tissues to RBCs.
Once next to lungs, low conc of CO2 so reaction is reversed.
Plama carries metabolies in solution.
Carries substances poorly soluble in H20 (lipids, HDL/LDLS/ Metal ions).
If blood is infected with bacteria - SEPTICEMIA. Bacterium uses iron to grow. So, iron is kept tightly bound to a plasma protein (transferrin - plasma glycoprotein). If a cell wants iron is has to bind to a transferrin receptor.
Specialised carrier –> TBG (Thyroxin binding globin).
Haemoglobin (6)
Protein Hb
Hb binds oxygen and carries it from lungs to tissues.
Tetramer, 4 polypeptide chains - 2a/b globin chains.
Each globin chain has a haem molecule, prosthetic Fe2+ group.
Oxygen binds reversibly to Fe via a coordination bond this process is oxygenation, NOT OXIDATION.
Around 3(8 0s) Hb in each RBC.
Pulse oximeter (3)
Measures colour of haemoglobin.
Determines is patient is hypoxic (deprived of O2).
When opioid drug used, it supresses breathing reflex so patient may become hypoxic so pulse oximeter is used to check. That’s why after an operation, a patient on morphine is constantly monitored.
Erythrocyte - Transport (5)
Plasma carries soluble metabolites in solution.
Plasma proteins carry substances which are poorly soluble in water e.g. lipids.
Plasma proteins may carry metal ions (can be toxic).
When blood becomes infected with bacteria called septicemia. so bacterium needs iron to grow, if body keeps it tightly bound to plasma protein, it is harder for bacteria to reach this.
Transferrin binds iron to blood takes it to the tissues keeps it away from bacteria. Cells which need iron have a protein receptor which binds transferrin and takes the iron.
Specialised carrier - Thyroxine binding protein (TBP) and Transferrin.
Erythrocyte - Defence (2,4)
• Immunity
WBC and plasma proteins
Innate immunity- Defence mechanisms you are born with.
Adaptive (acquired) Immunity you get after being exposed to a disease, you probably only catch it once.
• Clotting (aka haemostasis - the stopping of a flow of blood.)
Platelets and plasma proteins
WBCs (4)
Leukocytes Colourless Common types: o Neutrophils o Lymphocytes
Leukoplakia
White layer on gum. Leukoplakia is a condition in which thick, white patches form on your tongue and the lining of your mouth.