Final answer:
The portion of each lung that is directed medially, oriented vertically, indented, and serves as the area through which various structures pass is called the hilum or hilus.
Step-by-step explanation:
The portion of each lung that is directed medially, oriented vertically, indented, and serves as the area through which the bronchi, pulmonary vessels, lymphatic vessels, and nerves pass is called the hilum or hilus.
The hilum is a concave structure located on the mediastinal surface of the lungs. It acts as a gateway, allowing the passage of various structures into and out of the lung. Blood vessels, lymphatic vessels, nerves, and the primary bronchus enter the lung through the hilum.
This anatomical feature is essential for the proper functioning of the lungs, as it allows for the exchange of gases, removal of waste products, and transportation of essential nutrients and oxygenated blood.