Emergency Medical Technician (EMT) Intermediate Practice Exam

Which statement accurately describes the lung parenchyma?

1. It is covered by the visceral pleura

2. It has a smooth muscle layer for contraction

3. It is primarily composed of cartilage

4. It regulates blood flow to the heart

The correct answer is: It is covered by the visceral pleura

The lung parenchyma refers to the functional tissue of the lungs, including the alveoli (where gas exchange occurs), bronchioles, and supporting structures. It is primarily composed of alveoli and interstitial tissue, which facilitates the exchange of gases between air and blood. The statement indicating that the lung parenchyma is covered by the visceral pleura is accurate because the visceral pleura is the membrane that directly covers the surface of the lungs. This thin layer not only provides protection but also aids in the smooth movement of the lungs during respiration by allowing the lungs to expand and contract without friction against the surrounding structures. In contrast to the correct statement, the lung parenchyma does not have a smooth muscle layer for contraction, it is not primarily made of cartilage, and it does not regulate blood flow to the heart. Smooth muscles are present in the bronchi and bronchioles but not specifically in the parenchyma where gas exchange occurs. Cartilage is found in the larger airway structures like the trachea and bronchi, ensuring they maintain their shape, but it does not compose the parenchyma itself. Lastly, blood flow regulation to the heart is a role of different structures within the cardiovascular system