Lungs

lung The respiratory organ of air-breathing vertebrates. A pair of lungs is situated in the thorax, within the ribcage. Each consists essentially of a thin moist membrane that is folded to increase its surface area. Exchange of oxygen and carbon dioxide takes place between blood capillaries on one side of the membrane and air on the other. The lung is supplied with air through a bronchus. The lungs are covered by a thin tissue layer called the pleura. The same kind of thin tissue lines the inside of the chest cavity -- also called pleura. A thin layer of fluid acts as a lubricant allowing the lungs to slip smoothly as they expand and contract with each breath.

Respiratory depression

Respiratory depression is a broad medical term that is used to describe any condition in which an individual's respiration has a rate below 12 breaths per minute or that fails to provide full ventilation of the lungs. The symptoms for this condition can range greatly and, as such, must be monitored diligently in order to asses whether the health risks are minimal or suggestive of a much larger medical problem.