Mass Transport Flashcards
Haemoglobin structure
Quaternary protein made up of 4 polypeptide chains - 2 alpha and 2 beta.
Prosthetic group (haem group) containing an iron ion - gives blood its red colour.
How many oxygen molecules of oxygen can haemoglobin carry?
4 O2 molecules (or 8 atoms)
- they associate with the iron ion
High affinity haemoglobin
Associates/ loadswith O2 more readily, dissociates/unloads less readily
When there is a high partial pressure of oxygen
Low affinity haemoglobin
Dissociates/unloads more readily
When there is a Low partial pressure of oxygen
Loading and unloading of haemoglobin
Loads at lungs where there is a higher pO2 (saturated)
Unloads at respiring cells where there is a higher pCO2 and lower pO2 (unsaturated)
Why does the oxygen dissociation curve get steeper?
When the first O2 binds this causes a change in shape
Enables next O2 to bind (more readily able to load O2)
Factors that reduce affinity for O2
Higher CO2
Lower pH
Higher temperature
A shift to the…. Of the curve shows a reduced affinity
And a shift to the…. Of the curve shows a higher affinity
Right
Left
The Bohr shift
Respiring tissues release CO2
Reduces haemoglobin affinity
Unloads more O2 (to deliver to respiring tissues)
Which direction do arteries carry blood from the heart
Away from the heart to the body (arrive at the other organs)
Arteries
Thick, muscular walls
Elastic - recoil to maintain a high pressure
Branch into arterioles
Which direction to veins carry blood to the heart
Towards the heart (veIN - IN to the heart) (leave the other organs)
Veins carry blood at a lower pressure than arteries. What adaptation does this require?
Valves to prevent back flow of blood.
Capillaries
Endothelium one cell thick (short diffusion pathway) and flattened
Permeable
Form capillary networks - increases surface area for GE (I.e at the alveoli)
