ANATOMY & PHYSIOLOGY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site alveolus Alveoli in the lung A minute air-filled sac in the vertebrate lung. Pulmonary alveoli are thin-walled and surrounded by blood vessels. There are large numbers of alveoli in each lung, and it is through their surfaces that the respiratory exchange of oxygen and carbon dioxide occurs. In most vertebrates they connect with the mouth by a system of ramifying air-tubes – the bronchi and bronchioles. An expanded sac of secretory epithelium, which forms from an internal termination of each duct in many glands (e.g. the mammary glands). Dental alveolus: a cavity in the jaw-bone into which a tooth fits. Related category    • ANATOMY AND PHYSIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP