 Dear students, in this topic we shall discuss the lung volumes and capacities. The lung volumes refer to the volumes of air which are associated with different phases of the respiratory cycle. These volumes can be directly measured. The lung capacities can be inferred from the lung volumes. There are five types of malleable lung volumes. The resting tidal volume, inspiratory reserve volume, expiratory reserve volume, the residual volume and the minimal volume. The resting tidal volume is the amount of air that moves into or out of the lungs during a single, quite normal breathing. It averages about 500 millilitre in human, male and female both. We shall discuss the inspiratory reserve volume which is the amount of air which can be inhaled by maximum inspiratory effort. On average, the lungs of males are larger than females. So the inspiratory reserve volume of males is greater and the average is about 3,300 millilitre. We shall discuss the expiratory reserve volume which refers to the amount of air which can be voluntarily expelled out after the tidal volume by maximum inspiratory effort. A male can forcefully expel additional 1,000 ml air by use of accessory muscles while in females this amount is about 700 millilitres. The residual volume is the amount of air that still remains in the lungs even after maximum exhalation. It is about 1200 ml in males and 1,100 millilitres in females. A component of residual volume is the minimal volume. This is the amount of air that still remains in the lungs when they fully collapse. This volume ranges about 30 to 120 ml. Unlike other volumes, it cannot be measured in a healthy living person. Now we shall discuss the lung capacities which are calculated by adding the values of various lung volumes. These include inspiratory capacity, functional residual capacity, vital capacity and total lung capacity. The inspiratory capacity is calculated by adding the tidal volume and inspiratory reserve volume. It refers to the amount of air that can be drawn into the lungs after a complete respiratory cycle. The functional residual capacity can be calculated by adding expiratory reserve volume and residual volume. It refers to the amount of air which remains in the lungs after a complete respiratory cycle. Vital capacity refers to the maximum amount of air which can be moved into or out of the lungs in a single respiratory cycle. It is calculated by adding expiratory reserve volume, tidal volume and inspiratory reserve volume. Its overall amount is about 4800 ml in males and 3400 ml in human females. The total lung capacity refers to the total volume of the lungs. It is calculated by adding the vital capacity and residual volume. The total lung capacity in males averages about 6000 ml in human males and 4200 ml in human females.