A bronchus enters the lung at the ________ (an indentation on the medial surface of the lung).

Each lung (the right and left lungs) can be divided into four main sections: the apex, base, root, and the hilus, or hilum of the lung.

Hila, or lung roots, are relatively complicated structures that consist mainly of the major bronchi and the pulmonary arteries and veins.

The hilum of the lung is found on the medial aspect of each lung, and it is the only site of entrance or exit of structures associated with the lungs. That is to say, both lungs have a region called the hilum, which serves as the point of attachment between the lung root and the lung. Broadly speaking, this particular region of the lung can be described as a triangular, depressed area where a lot of anatomical structures enter and leave each lung.