Lower Portion of the Respiratory Tract

The **Larynx** is a cartilaginous structure responsible for producing the voice, preventing food and beverages from entering the trachea, and regulating the volume of air entering and leaving the lungs. The trachea is a tube composed of cartilaginous rings and supporting tissue, connecting the lung bronchi to the larynx and providing a pathway for air to enter and exit the lungs. As a major organ of the respiratory system, each lung contains structures for both the conducting and respiratory zones, with the primary function of exchanging oxygen and carbon dioxide with the atmosphere. The lungs are pyramid-shaped, paired organs that are connected to the trachea by the right and left bronchi, and their inferior surfaces rest against the diaphragm. The bronchi branch into smaller bronchioles, approximately 1 mm in diameter, and continue to subdivide into terminal bronchioles, leading to the gas exchange structures. Each lung contains over 1000 terminal bronchioles. *LICENSES AND ATTRIBUTIONS CC licensed content, Shared previously, Heather Ketchum and Eric Bright, Organs and Structures of the Respiratory System, Authored by: OpenStax College. License: CC BY: Attribution. License Terms: Download for free at http://cnx.org/contents/VflMihYl@1/OU-Human-Physiology-Organs-and* ## Keywords epiglottis ligament thyroid cartilage tracheal cartilage vocal cords respiratory system