Transport Of Gases Flashcards
3 types of blood cells?
- Erythrocytes : RBC
- Leucocytes : WBC
- Thrombocytes : Platelets
Role of plasma?
•It transports digested food products, hormones and proteins e.g fibrinogen, antibodies and distributes heat round the body
Erythrocytes?
• filled with haemoglobin
2 features that allow them to be efficient for transportation of O2
-large surface area ( biconcave shape )
•more efficient for diffusion in/out cell
- No nucleus
• more space in cell for haemoglobin to carry O2
Leucocytes? 2 groups.
- Granulocytes ; phagocytic, have granular nucleus. Contain lysosomes - vesicles containing digestive enzymes to destroy bacteria
- Agranulocytes ; produce antibodies/antitoxins They have a clear cytoplasm and spherical nuclei
Thrombocytes?
• involved in blood clotting
Haemoglobin?
• quaternary structure - 4 folded polypeptide chains
• @ centre of each polypeptide chains is an iron containing haem group
- each haem group is a binding site for oxygen
• one molecule of haemoglobin reacts readily with 4 O2 molecules to form HbO8
Composition of blood?
- Plasma is 90% water with a range of dissolved materials e.g vitamins, mineral ions, soluble food
- Blood Cells;
Haemoglobin?
- globular protein with a quaternary structure: 4 polypeptides folded
- at centre of polypeptide is an iron containing haem group
- each haem group is a binding site for O2
- one molecule of haemoglobin reacts with 4 O2 to make oxyhemoglobin
- Hb + 4O2 –>
Transport of oxygen?
- O2 diffuses into RBC and reacts with haemoglobin to form oxyhaemoglobin
- O2 conc measured in partial pressure - O2 tension
- when partial pressure is high e.g lungs, O2 binds with haemoglobin to form oxyhaemoglobin
- when partial pressure is low e.g respiring tissue, oxyhaemoglobin dissociates from the haemoglobin
Name for a O2 dissociation curve?
• sigmoidal
Foetal haemoglobin?
- O2 dissociation curve shifted to left of adult curve
* means it has a higher affinity for O2 so can absorb O2 from mothers blood at all partial pressure of O2
Advantages of foetal haemoglobin’s position?
- it has a higher affinity for O2 than adult so it can easily pick up O2 and readily make oxyhaemoglobin
- reached saturation at low partial pressures to ensure O2 moves from mothers blood to foetus in placenta
Llama and lungworm haemoglobin?
- llamas live in high altitudes, increase in altitude = drop in atmospheric pressure so a reduction in partial pressure of O2
- to compensate, llamas haemoglobin has a higher affinity for O2 so picks up O2 more readily at lungs
- curve is shifted to left
- high altitudes means more red blood cells
Lugworms absorb O2 from seawater they pink through burrow
- in order to cope with the low O2 conc of seawater they have a dissociation curve shifted to left to readily take in O2
Facts:
• when mammals are moved to high altitudes, they make more erythrocytes in their blood so there is more haemoglobin to bind with more O2
Myoglobin?
- more stable than haemoglobin : acts as an O2 store in muscles
- dissociation curve far left of haemoglobin
- for every partial pressure of O2, myoglobin has a higher % O2 saturation than haemoglobin
• if ppO2 becomes low e.g during exercise, oxymyglobin unloads it’s O2
