What is a Promise Ring. A promise ring, sometimes known as a pre-engagement ring, is a simple piece of jewelry that is given as a symbol of a committed, monogamous relationship. In some cases, the promise ring symbolizes purity and a decision to remain celibate until marriage.
Noun. 1. external respiration-the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation. breathing, respiration, ventilation. artificial respiration-an emergency procedure whereby breathing is maintained artificially.
Pulmonary ventilation is the movement of air into and out of the lungs (breathing). External respiration is the exchange of O2 (loading) and CO2 (unloading) between blood and alveoli (air sacs). Transport of respiratory gases between lungs and tissues.Internal respiration is gas exchange between blood and tissue cells.ulmonary ventilation is the movement of air into and out of the lungs (breathing). External respiration is the exchange of O2 (loading) and CO2 (unloading) between blood and alveoli (air sacs). Transport of respiratory gases between lungs and tissues.