Oxygen is primarily part of the respiratory system, but its transport and use involve the circulatory system as well.
The Respiratory System's Role
The respiratory system's main function is to facilitate the intake of oxygen and the expulsion of carbon dioxide. This process, known as breathing or respiration, involves several organs working together:
- Lungs: The primary organs of gas exchange. Air enters the lungs, and oxygen passes from the air sacs (alveoli) into the bloodstream.
- Airways: The trachea (windpipe), bronchi, and bronchioles conduct air to and from the lungs.
- Diaphragm: A muscle that helps control breathing.
- Nose and Mouth: Entry points for air.
As stated by the National Heart, Lung, and Blood Institute (NHLBI), "When you breathe in, air enters your airways and travels down into the air sacs, or alveoli, in your lungs. This is where gas exchange takes place." (https://www.nhlbi.nih.gov/health/lungs/respiratory-system) The American Lung Association also highlights that the respiratory system's main job is to transport oxygen and remove carbon dioxide. (https://www.lung.org/lung-health-diseases/how-lungs-work).
The Circulatory System's Role
Once oxygen enters the bloodstream in the lungs, the circulatory system takes over. The circulatory system, including the heart and blood vessels, transports oxygen-rich blood to all the body's cells.
- Blood: Carries oxygen bound to hemoglobin in red blood cells.
- Heart: Pumps blood throughout the body.
- Blood vessels: Arteries, veins, and capillaries deliver oxygen to cells.
The circulatory system's role in oxygen transport is explicitly mentioned in resources like the one found on the National Center for Biotechnology Information website: "The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body." (https://www.ncbi.nlm.nih.gov/books/NBK279250/)
In summary, while oxygen initially enters the body through the respiratory system, its distribution and utilization throughout the body depend on the circulatory system.
