Lungs: facts, function and diseases


LUNGS are sacks of tissue located just below the rib cage and above the diaphragm. They are an important part of the respiratory system and waste management for the body. A person’s lungs are not the same size. The right lung is a little wider than the left lung, but it is also shorter. According to York University, the right lung is shorter because it has to make room for the liver, which is right beneath it. The left lung is narrower because it must make room for the heart.
Typically, a man’s lungs can hold more air than a woman’s. At rest, a man’s lungs can hold around 750 cubic centimeters (about 1.5 pints) of air, while a woman’s can hold around 285 to 393 cc (0.6 to 0.8 pints) of air, according to York University. “The lungs are over-engineered to accomplish the job that we ask them to do,” said Dr. Jonathan P. Parsons, a professor of internal medicine, associate director of Clinical Services, and director of the Division of Pulmonary, Allergy, Critical Care and Sleep Medicine at the OSU Asthma Center at The Ohio State University. “In healthy people without chronic lung disease, even at maximum exercise intensity, we only use 70 percent of the possible lung capacity.”
According to the American Lung Association, adults typically take 15 to 20 breaths a minute, which comes to around 20,000 breaths a day. Babies tend to breath faster than adults. For example, a newborn’s normal breathing rate is about 40 times each minute while the average resting respiratory rate for adults is 12 to 16 breaths per minute.
Though breathing seems simple, it is a very complex process. The right lung is divided into three different sections, called lobes. The left lung has just two lobes. The lobes are made of sponge-like tissue that is surrounded by a membrane called pleura, which separates the lungs from the chest wall. Each lung half has its own pleura sack. This is why, when one lung is punctured, the other can go on working.
The lungs are like bellows. When they expand, they pull air into the body. When they compress, they expel carbon dioxide, a waste gas that bodies produce. Lungs do not have muscles to pump air in and out, though. The diaphragm and rib cage essentially pump the lungs.
As a person breathes, air travels down the throat and into the trachea, also known as the windpipe. The trachea divides into smaller passages called the bronchial tubes. The bronchial tubes go into each lung. The bronchial tubes branch out into smaller subdivisions throughout each side of the lung. The smallest branches are called bronchioles and each bronchiole has an air sac, also called alveoli. There are around 480 million alveoli in the human lungs, according to the Department of Anatomy of the University of Göttingen.