Physiology Of COPD

In order to understand how COPD occurs one must understand the normal physiological processes of the lungs as well as the mechanism for loss of homeostatic control of the lungs. The air that we breathe in takes a specific path. Once air has entered the body it travels down the windpipe and to the bronchial tubes of your lungs. The bronchial tubes branch into many smaller bronchioles and at the end of these branches are air sacs called alveoli (NIH). The alveoli are not special on their own. Oxygen enters the blood via the alveolar wall and into the capillaries, small blood vessels that innervate the air sacs. The airways and alveoli are stretchy to allow for normal filling and deflation. In COPD, less air flows in and out of the pathways due
to less elastic air sacs, destroyed air sacs, walls of the airways are inflamed, or the airways become clogged with excess mucus (NIH). Emphysema and chronic bronchitis are the two major causes of COPD. Emphysema is a lung disease that causes the breakdown the alveolar walls and elastic fibers (Mayo). Whereas chronic bronchitis is when the bronchial tubes become inflamed and often blocked because the lungs produce too much mucus.