O2 transport extra

• O2 in solution:

  • PaO2 is concentration O2 in plasma
  • 1.5% O2 is transported in plasma
  • But is an inefficient means of transport
  • WHY is so little O2 Tx this way? - as its not very soluble
• O2 and Haemoglobin:

  • 98% of O2 binds to Haemoglobin
  • forming oxyhaemoglobin (HbO2 )
  • every haemoglobin molecule can bind with 4 O2 molecules, when all 4 binding sites are loaded with O2, it is said that the haemoglobin is fully saturated and able to transport 20 mls of O2 per 100 mls of blood
  • rapid and reversible binding process - at lungs o2 binds with haemoglobin and at tissues o2 dissociates from haemoglobin
• Haemoglobin's changing affinity for O2:

  • Maximises O2 binding at lungs
  • Facilitates O2 release at tissues
  • Produces sigmoid shaped oxygen dissociation curve