explain transport of gases through blood in humans ?

Transport of Gases − Oxygen and Carbon dioxide

• Gases transported by blood

• Oxygen − 97% through RBC
  3% in plasma in dissolved state

• Carbon dioxide − 20-25% through RBC
  70% as bicarbonate
  7% in plasma in dissolved state

Transport of Oxygen

• Oxygen binds with haemoglobin to form oxyhaemoglobin.

• 1 molecule of haemoglobin carries 4 molecules of oxygen.

• Formation of oxyhaemoglobin depends upon − pO₂, pCO₂, pH, temperature

• In alveoli − pO₂ (high), pCO₂ (low), pH (high) temperature (low) 
  Hence, oxyhaemoglobin forms.

• In tissues − pO₂ (low), pCO₂ (high), pH (low) temperature (high)
• Hence, oxyhaemoglobin dissociates

Transport of Carbon Dioxide

.

• CO₂ is carried as carbamino-haemoglobin by blood.

• When pCO₂ (high), pO₂ (low) − binding of CO₂ occurs (as in tissues)

• When pCO₂ (low), pO₂ (high) − dissociation of CO₂ occurs (as in alveoli)

• CO₂ is bound with haemoglobin in tissue and dissociates in alveoli where it is released.

• CO₂ is transported as bicarbonate as well.
  

• When pCO₂ (high), forms (in tissues)

• When pCO₂ (low), CO₂ + H₂O forms (in Alveoli)

• CO₂ is trapped in tissue as  and released in alveoli.

• For 100 mL of deoxygenated blood, about 4 mL of CO₂ is delivered to alveoli.