9. How does exchange of gases takes place in alveoli? - In alveoli the concentration of oxygen is higher and that of carbon dioxide is low as compared to concentration of these gases in the blood capillaries.
- Difference in concentration results in the exchange of gases due to simple diffusion.
- Oxygen diffuses into the blood and carbon dioxide diffuses out.
10. In large animals, diffusion pressure alone
cannot carry oxygen to all body parts. How is
this problem solved in these organisms? In large animals, diffusion pressure alone cannot carry oxygen to all body parts. To solve this problem animals have respiratory pigment in blood, which carry oxygen to all body parts during circulation. In human, this respiratory pigment is haemoglobin. 11. Name the pigment present in the red blood corpuscles which is responsible for transport of oxygen. Haemoglobin 12. How are gases carried through blood? The process of transport of gases through blood is as follows: Transport of oxygen- Oxygen gas enters blood in the alveoli region of the lungs.
- Blood contains respiratory pigment haemoglobin which has high affinity for oxygen
- Oxygen binds with haemoglobin and is then is then carried to various body parts through blood circulation.
- In the tissue region oxygen diffuses from blood to the tissue.
Transport of carbon dioxide - Tissue have more concentration of carbon dioxide which diffuses into the blood. - CO2 is mainly transported in the dissolved form through blood plasma.
- Once blood reaches alveoli, CO2 diffuses out
into the lungs. | 
