What is the primary characteristic of epithelial tissue?

The primary characteristic of epithelial tissue is that it is composed of sheets of tightly packed cells. This configuration allows epithelial tissue to form protective barriers and to function effectively in absorption, secretion, and sensation. The cells are closely bound together by tight junctions and desmosomes, which create a selective barrier and help maintain the integrity of the tissue.

This tight packing is essential for the various roles that epithelial tissue plays in the body, such as lining body surfaces and cavities, forming glands, and facilitating exchanges of materials. The organization of cells also allows for efficient communication between neighboring cells, ensuring coordinated responses to stimuli.

In contrast, loosely connected cells would not provide the necessary structural integrity or functionality typically associated with epithelial tissue. Fibrous cells imply a connective tissue type rather than epithelial, and elastic cells suggest properties more characteristic of certain connective tissues that exhibit elasticity. Thus, the tight packing of epithelial cells is fundamental to their structure and function.