The H&E stained tissue shown below was obtained by lobar biopsy and fixed in the inflated state by its major airway. The asterisk (*) is in what type of structure?
a. Respiratory bronchiole
The most correct answer is b, alveolar duct.
Note in this image the circumferential orientation of many alveolar openings around the central conduit or opening in the center, which itself has poorly defined walls that are interrupted by the pillar-like posts at the proximal ends of each.
Which of the following structures travel within the fibrous connective tissue septa between lung lobules?
a. Pulmonary veins and pulmonary arteries
b. Pulmonary veins and bronchial arteries
c. Bronchial veins and bronchial arteries
d. Pulmonary veins and lymphatics
e. Pulmonary arteries and lymphatics
The most correct answer is d, pulmonary veins and lymphatics.
Pulmonary arteries and bronchial arteries travel together adjacent to airways, although pulmonary arteries are much more commonly seen. Bronchial veins have never been convincingly demonstrated in the human lung.
The H&E stained tissue shown in upper right column was obtained by lung biopsy from a healthy donor. The asterisk (*) is in the lumen of what type of structure?
e. Large lymphatic vessel
The most correct answer is a, pulmonary artery.
Noting the prominent airway below the structure in question with its pseudo-stratified columnar epithelium, only one other structure listed among the possible answers could be correct (answer c), but this would be a very large bronchial artery. All other choices either travel along the interlobular septa (answers b and e) or do not exist (answer d).
Shown below is a photomicrograph of an H&E stained section of normal adult lung tissue. The asterisk (*) is in the lumen of which type of structure?
a. Larynx above the ventricle
b. Larynx below the ventricle
The most correct answer is c, bronchus.
The presence of a smooth muscle layer that is deep to the epithelium rules out choices a, b, and d. The external muscles of the larynx as well as the vocalis muscle are all skeletal muscles. Note that the structure in question has cartilage (left side of image) and a few seromucinous glands, both of which rule out choice e.