Physiology, Respiratory Rate

Excerpt

Respiration is a vital process for normal function at every level of organization from a cell to an organism; oxygen, supplied by local circulation at the tissue level, functions at the mitochondrial internal membrane as an essential mediator for energy release. In mitochondria, digested nutrients undergo metabolic reactions, end up at the level of the electron transport chain, and release high-energy compounds (eg, adenosine triphosphate). The main byproduct of this process, carbon dioxide, gets released in the venous blood, returning to the lungs. Carbon dioxide diffuses through alveolar walls and dissolves in exhaled air. The respiratory rate (ie, the number of breaths per minute) is highly regulated to enable cells to produce the optimum energy at any given occasion. A complex nervous system of nerve tissues governs the rate of oxygen inflow and carbon dioxide outflow. It adjusts it accordingly in conditions that derange partial gas pressures in blood. Respiration involves the brain, brainstem, respiratory muscles, lungs, airways, and blood vessels. All these structures have structural, functional, and regulatory involvement in respiration.