The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. In terrestrial animals, this is accomplished by breathing. The human body needs oxygen to sustain itself. A complete lack of oxygen is known as anoxia and a decrease in oxygen is known as hypoxia. After four to six minutes brain cells without oxygen brain cells are destroyed and an extended period of hypoxia leads to brain damage and ultimately death.
In humans, the average rate of breathing is dependent upon age. Newborns up to 6 weeks take 30 to 60 breaths per minute, while the average resting respiratory rate for adults is 12 to 20 breaths per minute. Physical exertion also has an impact on respiratory rate and healthy adults can average 45 breaths per minute during strenuous exercise.
Description of the respiratory system
The primary organs of the respiratory system are lungs, which function to take in oxygen and expel carbon dioxide as we breathe. Red blood cells collect the oxygen from the lungs and carry it to the parts of the body where it is needed. During the process, the red blood cells collect the carbon dioxide and transport it back to the lungs, where it leaves the body when we exhale.
The exchange of oxygen and carbon dioxide occurs in the alveoli, the tiny sacs that are the basic functional component of the lungs. The alveolar walls are extremely thin (about 0.2 micrometers). These walls are composed of a single layer of epithelial cells and the pulmonary capillaries.
The trachea, also called the windpipe, filters the air that is inhaled. It branches into the bronchi, which are two tubes that carry air into the lungs.
The diaphragm, a dome-shaped muscle at the bottom of the lungs, controls breathing. When a breath it taken, it flattens out and pulls forward, making more space for the lungs. During exhalation, the diaphragm expands and forces air out.
Diseases of the respiratory system
Common diagnostic tools for diagnosing respiratory disease include chest x-ray, pulmonary function test and CT scan. A bronchoscopy is performed by inserting a bronchoscope into the airways — usually through the nose or mouth — to examine for bleeding, tumors, inflammation or other abnormalities.
Diseases and conditions of the respiratory system can be caused by the inhalation of foreign bodies such as cigarette smoke, chemicals, allergens and other irritants. Not all people will develop respiratory ailments as a result of environmental factors, as genetics also play a role in the development of respiratory diseases.