tenâ¢or /ËtÉnÉ/USA pronunciation n. the course of meaning that runs through something written or spoken; drift:[countable]The tenor of the meeting was one of tenseness. continuous course or movement:[countable]nothing to disturb the tenor of our lives. Music and Dance [uncountable] the adult male voice between the bass and the alto.
The pulmonary artery carries deoxygenated blood from the heart to the lungs and is the only artery in the body that carries deoxygenated blood. The pulmonary vein carries oxygenated blood from the lungs to the heart, and it is the only vein that carries oxygen-rich blood.
The circulatory system includes the heart, blood vessels, and regulatory controls (such as the autonomic nervous system, catecholamines, and hormones). Its main function is to deliver oxygen and substrate (glucose) to cells. The circulatory system also transports byproducts of cellular metabolismâ66% in the form of carbon dioxide (CO2) to the lungs and the remaining 33% to the kidneys as breakdown products of protein metabolism.