CO2 Concentration

• What does CO2 concentration affect?

  oxygen unloading
• When does Hb give up its oxygen more readily?

  At a higher partial pressure of carbon dioxide
• What happens when cells respire?

  They produce carbon dioxide which raises the pCO2 
• What does the raised pCO2  increase?

  The rate of oxygen unloading (ie the rate at which oxyhaemoglobin dissociates to form haemoglobin and oxygen)- so the dissociation curve shifts right

  The saturation of blood with oxygen is lower for a given pO2 , meaning that more Oxygen is being released

  This is called the BOHR EFFECT
• how does increasing co2 conc increase the dissociation of oxygen?

  Decreasing pH of blood/ increases acidicty
• Describe a Bohr Shift?

  • The greater concentration of CO2,
  • the more readily Hb releases its O2
  • because the more CO2 there is,
  • the lower the pH,
  • the greater the Hb shape change,
  • the more readily O2 is unloaded,
  • the more O2 available for respiration