The cardiorespiratory system is comprised of two separate sets of organs that rely on one another to function properly. It includes the heart as well as arteries, veins, and capillaries, which enable oxygen exchanged by the lungs to pass into the bloodstream to the cells. Respiratory organs include the lungs, diaphragm, bronchi, and mouth and nose, through which oxygen is directed toward air sacks and absorbed into the blood stream. The gas exchange between oxygen and carbon dioxide is a process a person cannot live without. Adequate exercise can increase the capacity of the lungs and the strength of the heart so more blood can be pumped, and more oxygen absorbed.
Air with oxygen passes into the cardiorespiratory system from the mouth and nose through the trachea, bronchi, and bronchiole tubes. Deep in the lungs are air sacks called alveoli where oxygen passes into the blood and carbon dioxide is removed from the bloodstream. A network of capillaries surrounds the thin cellular layer in the alveoli, and transport oxygen to the body via the pulmonary artery. One of the most important respiratory organs is the diaphragm, a muscle that helps moves the lungs in order in inhale and exhale air. Lungs are not muscular organs, so athletic exercise often focuses on the diaphragm to increase lung capacity.
The heart consists of four chambers which enable blood to enter, pass through the lungs, and exit to the rest of the body. Valves help move the blood in the right direction and, the stronger the heart is, the more blood it can push out each time it beats. For athletes, this means that the cardiorespiratory system can transport greater amounts of oxygen and nutrients to different areas of the body quicker. Training requires an understanding of how much oxygen can be breathed in during each minute. The measure is often made in comparison to an athletic person’s weight to determine an optimal exercise level.
Cardiorespiratory system function is also determined at the cellular level. When a person exercises frequently, it triggers the formation of mitochondria inside cells. Mitochondria make a substance called Adenosine Triphosphate (ATP) which is used by the body as energy. Enzymes also aid in the body’s ability to make efficient use of oxygen. In addition to exchanging respiratory gases, the cardiorespiratory system takes out lactic acid, urea, and other metabolic wastes, regulates the acidity of blood, and moves enzymes and hormones throughout the body.