Haemoglobin and oxygen

• red blood cells have concave shape - large surface area for absorption of oxygen
• each haemoglobin carries four molecules of oxygen
• oxyhaemoglobin releases oxygen in oxygen poor situations
• Haemoglobins affinity - ability to pick up and combine with oxygen - changes with partial pressure of oxygen
• high partial pressure of oxygen means Hb has a high affinity for oxygen - readily picks up and combines with oxygen to form oxy Hb
• low partial pressure of oxygen mean Hb has A lower affinity for oxygen so oxy Hb dissociates from oxygen - real easing and reforming Hb
• low partial pressure - low affinity - unloading