Respiratory Anatomy and Histology

  • The primary function of the lung is a gas exchange. To do so, the lung brings oxygen-rich, carbon dioxide-poor gas from the external environment into extremely close contact with oxygen-poor, carbon dioxide-rich venous blood returning from the systemic circulation.
  • As a result, the lung can be thought of as containing three functional anatomical features: 1) The interface where blood and gas are brought into close contact, 2) The airways which bring external air to these gas exchange surfaces, and 3) The vasculature which brings external air to these gas exchange surfaces. We discuss the anatomical and histological features of these three basic components in the sections below. However, we provide a quick description of the lung's gross anatomy.