| Some details about lungs |
Humans have two lungs, with the left being divided into 2 lobes and the right into 3 lobes. These contain approximately 1500 miles of airways and 300 million alveoli, having a total surface area of about 140m2 in adults - roughly the same area as a tennis court.
Total lung capacity includes inspiratory reserve volume, tidal volume, expiratory reserve volume, and residual volume. The total lung capacity depends on the person's age, height, weight, sex. It ranges between ca. 4,000-6,000 cm3. For example, females tend to have a 20-25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. Smokers have a lower capacity than nonsmokers. Lung capacity is also affected by altitude. A person who is born and lives at sea level will have a smaller lung capacity than a person who spends their life at a high altitude. In addition to the total lung capacity, one also measures the tidal volume, the volume breathed in with an average breath, about 500 cm3. For a detailed discussion of the various lung volumes, see the article on lung volumes.
Typical adult resting breathing pattern has a breath rate of 10-20 breaths per minute with 1/3 of the breath time in inspiration.
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