Foetal Haemoglobin

• Different structure to maternal haemoglobin; different oxygen affinity, both sigmoid curves but foetal haemoglobin (HbF) lies to the left of maternal haemoglobin: it has a higher affinity than the maternal haemoglobin, and can take up oxygen from the it
• At lower ppO_2; oxygen transference between these two haemoglobins occurs over the placenta (as bloods come in close contact), placenta tissue has low ppO_2 which causes the maternal oxyhaemoglobin to dissociates, releasing oxygen
• The Graph:

  A) Foetal Haemoglobin

  B) Adult Haemoglobin