It is here that the gaseous exchange occurs the oxygen of the atmospheric air is transferred to the blood and carbon di oxide of the blood to the air spaces. With each inhalation we take in oxygen rich air and with each exhalation we let out carbon di oxide rich air into the atmosphere. Plants and trees absorb this carbon dioxide as their food and release oxgen into the air. Lungs are directly exposed to the outside atmosphere through the trachea and bronchi. The atmosphere around us, particularly in towns and cities, is polluted with noxious materials such as dust, smoke, fumes, bacteria, viruses, etc.
0 comments:
Post a Comment