At which one of the following sites simple squamous epithelium is not present ?
a) alveoli of lungs b) bronchus c) endothelium d)
mesothelium
Answers
Explanation:
Before studying the histology of any particular system or organ, one should appreciate the basic concepts and tools of histology, as presented in the Introduction to Histology at this website. In particular, one should be familiar with the four basic tissue types, most especially epithelium and connective tissue and with the basic tools of histology.
Overview of Respiratory Tract Histology
The lung is one of several organs that packs a large epithelial surface area into a compact volume. The basic organizational pattern is that of a gland, in which a branching tree of tubes provides continuity from the body's outside surface to a vast number of epithelial cells. Indeed, the respiratory tract begins life as an invagination of epithelial (endodermal) tissue, and embryonic lungs even have the histological appearance of compound, exocrine glands. Only fairly late in development do the cuboidal epithelial cells of the terminal alveoli assume the thin squamous shape that characterizes the lining of mature gas-exchanging air sacs. And some significant secretory function is retained, in the form of cuboidal, surfactant-producing great alveolar cells.