Define the following terms? a. Tidal vo | Class 11 Biology Chapter Breathing and Exchange of Gasses, Breathing and Exchange of Gasses NCERT Solutions

The quantities of air the lungs can receive, hold or expel under different conditions are called pulmonary or lung volumes. Tidal volume or Residual volumes are one of them. 

1. Tidal volume: It is the volume of air normally inspired or expired in one breath without any effort which is about 500 ml. in actual, only 350 ml (alveolar volume) air enters the lung alveoli for the gaseous exchange and the remaining 150 ml (dead space volume) fill the respiratory passage.
2. Residual volume: Some air always remains in the lungs even after forcible respiration, this amount of air is known as residual volume which is about 1500ml.
3. Asthma: It is a diseased condition in which airways become narrow and swells and can also produce extra mucus. These conditions can make difficulty in breathing, coughing, shortness of breath etc.