What is the primary function of epithelial tissue?

Epithelial tissue primarily functions in absorption and secretion, making it essential for many physiological processes. This type of tissue forms the coverings and linings of organs and body cavities, creating barriers that can selectively allow substances to enter or exit. For example, in the intestines, epithelial cells are responsible for absorbing nutrients from the digested food, while in glands, epithelial tissue produces and secretes hormones, enzymes, and other substances.

Epithelial cells also often feature tight junctions, which help to regulate the passage of materials, further emphasizing their role in absorption and secretion. Moreover, their structure is adapted for these functions, with some epithelial cells having microvilli or cilia that increase surface area or aid in the movement of substances.

In contrast, while transport of materials is a function associated with certain types of specialized tissues, it is not the primary function of epithelial tissue as a whole. Connective tissue is specifically responsible for supporting and connecting other tissues, and nerve tissue is designed to conduct impulses rather than absorb or secrete. Thus, absorption and secretion encapsulate the essential roles of epithelial tissue within the body.