Pulmonary of pulmonary ventilation. Pulmonary volumes and capacities vary

Pulmonary air volumes refer to the set of average volumes that can be applied to certain aspects of pulmonary ventilation. Pulmonary volumes and capacities vary from person to person depending on their age, relative size, and build.There are four major pulmonary volumes: tidal volume, residual volume, expiratory reserve volume and inspiratory reserve volume. The relative sums of these volumes make up the pulmonary capacities. Tidal volumeThe tidal volume is the volume of air inhaled or exhaled with one normal breath. The tidal volume multiplied by the respiratory rate (number of breaths per minute) gives the minute ventilation.VolumeIt is typically about 500 ml.Residual volumeResidual volume refers to the volume of air that remains in the alveoli after a forced expiration.VolumeIt is typically about 1,100 ml in females and 1,200ml in males.Expiratory reserve volumeThe expiratory reserve volume is the volume of air that can be forcefully expelled from the lungs after a normal expiration.VolumeIt is typically about 700 ml in females and 1,200ml in males.Inspiratory reserve volumeThe inspiratory reserve volume is the additional volume of air you can inspire following a normal inspiration.VolumeIt is typically about 1,900 ml in females and 3,100 ml in males.Minimal volumeThe minimal volume refers to the remaining air in the lungs after some of the residual volume has been forced out. This volume is only measurable after the thoracic cavity has been opened and the intrapleural and atmospheric pressures have been equalized. It is used to determine if a baby is stillborn or died after birth.There are four major pulmonary capacities: inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity:Inspiratory capacityThe inspiratory capacity is the volume of air that can be inspired normally, in addition to any air that can be inspired forcefully.EquationTidal volume + inspiratory reserve volumeVolumeIt is typically about 2,400 ml in females and 3,600 ml in males.Functional residual capacityFunctional residual capacity refers to the volume of air left in the lungs after a normal expiration.EquationExpiratory reserve volume + residual volumeVolumeIt is typically about 1,800 ml in females and 2,300 ml in males.Vital capacityVital capacity refers to the maximum volume of air that can be exhaled from the lungs after maximum inspiration and is a measure of lung function.EquationInspiratory reserve volume + expiratory reserve volume + tidal volumeVolume:It is typically about 3,100 ml in females and 4,800 ml in males.Total lung capacityTotal lung capacity refers to the volume of air that can be contained within the lungs after maximal inspiration.EquationVital capacity + residual volumeVolumeIt is typically about 4,200 ml in females and 6,000 ml in males.Anatomic dead space refers to the conducting airways of the respiratory system that are not directly involved in gaseous exchange. These include the airways that transport air to the respiratory membrane but do not provide a selectively permeable membrane through which the gases can diffuse, e.g. the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.Not all the air in each breath is used for the exchange of carbon dioxide and oxygen. Approximately a third of every resting breath occupies anatomic dead space. For that reason, not all of the minute ventilation can be used in gas exchange