Bronchial Tree: Anatomy and Function

Where does the trachea branches into the right and left mainstream bronchi?

Is it at A. Cricoid, B. Apex of the pleural cavity, C. Apex of the diaphragm, or D. Carina?

Answer:

The trachea branches into the right and left primary bronchi at the carina. This point marks the beginning of the bronchial tree, a network of air passageways leading to the site of gas exchange in the lungs, the alveoli. D. Carina

Explanation:

The trachea, or windpipe, branches into right and left paths known as the primary bronchi at an anatomical structure called the carina. Supported by rings of cartilage similar to those of the trachea, this splitting of the trachea into the bronchi happens as it enters the lungs. The carina is a raised structure that contains specialized nervous tissue. When a foreign body like food is present, it induces violent coughing, helping to keep the airway clear. The bronchi continue their division into progressively smaller passageways, forming what is collectively called a bronchial tree. As these structures continue to branch within the lungs, they lead to the site of gas exchange, the alveoli.