Oxygen Transport

Key terms

• Affinity - The tendency a molecule has to bind
• Association - Two things bind together   

Oxygen (O₂) + Haemoglobin (Hb) -> Oxyhaemoglobin (2HbO)

• Disassociation - The splitting into two

Oxyhaemoglobin (2HbO) -> Haemoglobin (Hb) + Oxygen (O₂)

• Partial Pressure - concentration of oxygen in the blood
  
• pO₂ -  The partial pressure of oxygen
• SaO₂ -  - Percentage of haemoglobin saturated with oxygen (oxyhaemoglobin) in the total haemoglobin of the blood. i.e. the ‘oxygen concentration’ of the blood. 95-99%
• Blood pressure -  Is a measure of the force that your heart uses to pump blood around your body.

Haemoglobin

• Each red blood cell contains several 100,000 haemoglobin molecules to transport oxygen
• It is a large protein with a quaternary structure - it has four polypeptide chains. Each chain has a haem group which contains iron and gives it it's red colour. 
• Each molecule can carry four oxygen molecules. 
• In the lungs, oxygen joins to the iron to form oxyhaemoglobin. 
• This is a reversible reaction. 
• When an oxygen molecule joins it is known as association or loading. and when it leaves it is dissociation or unloading.

Affinity for Oxygen and pO₂

• The affinity varies depending on the conditions
• The greater the concentration…