Vital capacity of lungs

Vital capacity (VC) - the maximum amount of air that can be taken into the lungs after the maximum expiratory.
Adult healthy person with a calm inhale and exhale inhales and exhales about 500 cm3 air. This is called the breathing air. However, after a relaxing breath, you can optionally breathe some air, the so-called additional, its volume is about 1500 cm3. After a restful exhale, you can optionally out more about 1500 cm3 air. This so-called back-air.
Thus, the vital capacity is the sum of additional, respiratory and reserve amounts and is equal to 3500 cm3.
Even after the deepest breath in the lungs there are still about 800 - 1700 cm3 of the air, the so-called residual air.
Residual and reserve air constantly fill the alveoli of the lungs during quiet breathing. This so-called alveolar air. Amount equal 2500-3500 cm3. It is the alveolar air is involved in continuous gas exchange between the lungs and blood, making as if internal gas medium of the organism (see Gas exchange, Breath).
The amount of additional and respiratory volumes defines inspiratory capacity of the lungs, the sum of respiratory and backup volumes characterizes them expiratory power.
Vital capacity of lungs, inspiratory and expiratory power first of all depends on physical development, training and physique. They significantly change with the disease of the lungs and cardiovascular system. Special training quickly leads to an increase in VC. Thus, the definition of lung capacity is one of the most important methods of clinical and clinical studies of people.
The definition of lung capacity - see Spirometry.
Vital capacity of lungs in children - the value of more labile than adults. In children of early age it depends on several factors: age, gender, height, circumference of breast, mobility of the diaphragm and chest, health, degrees of training and other
Reduced lung capacity in children occurs in certain pathological conditions of the lungs (such as fibrosis of any etiology, atelectasis, diffuse bronchitis, bronhiolospazm, condition after resection), pleura (adhesions, pleural overlay, hemo-, PIO - and pneumothorax), chest (expressed deformation, condition after thoracotomy).
Diagnostic significance reduced lung capacity below 80% of its value. Should the value of vital capacity of the lungs should equal the value of the basic currency multiplied by (the correlation coefficient was found empirically). Should the value of the basic currency is determined by body weight, height, gender and age at the tables. For children 4 years - 1,4; 5-6 years - 1,5; 7-9 years - 1,65; 10-13 years - 1,75; 14-15 years to 2.0. For adults is 2.3.