Question

Alveoli of lungs are lined by
A. Squamous epithelium
B. Columnar epithelium
C. Cuboidal epithelium
D. Stratified cuboidal epithelium

Answer 1

Hint: The various body cavities and hollow organs are covered by the widespread epithelial tissue. epithelial tissue has a variety of functions including protection, secretion, absorption excretion, filtration diffusion, and sensory receptors. Epithelial tissues are characterized by various shapes and arrangements of cells.

Complete answer:
The connective tissues are special tissues that perform the function of linking and supporting other tissues or organs of the body. The tissue originates from the mesodermal tissue of the embryo. Epithelial tissues consist of various shapes and cells that lie wide apart in a large amount of nonliving intercellular or extracellular material called matrix.
Epithelial tissue is classified on the basis of cell layers and the shape of a cell typically there are two types of epithelial tissues; simple and compound epithelial tissue. Simple epithelium is further classified as epithelium, cuboidal epithelium, columnar epithelium, the ciliated epithelium on the basis of their cell form and structure.
The epithelium consists of thin flat disc-like cells that are closely fitted like tiles on the floor and also called pavement epithelium. The main function of Squamous epithelium is that they allow materials to pass through via diffusion and filter and secrete some lubricating substances.

Option B- Columellar epithelium is present on the ciliated tissues in bronchi and uterus and in smooth non-ciliated tissues found in the digestive tract they absorb and secrete mucus and some enzymes.

Option C- Cuboidal epithelium is mainly found on duct and secretory portions of small glands and in kidney tubules; they mainly secrete and absorb.

Option D- Stratified cuboidal epithelium, they are located mainly on sweat glands, salivary glands, and mammary glands and they function as protective tissue.

So the correct answer is option A. Squamous epithelium.

Note:
The main function of epithelium tissue is to provide protection and help in excretion, gas exchange, and secretion of coelomic fluid. The lining of blood vessels and alveoli are lined by surface epithelium as they easily allow the materials to pass through by diffusion and let them to filter and secrete some lubricating substances.