Final answer:
The epithelial tissue, also known as epithelium, functions as a protective barrier and lines surfaces, hollow organs, and cavities. Gland cells that migrate below this layer form glands, secreting necessary substances for bodily functions. This tissue is different from muscle tissue, which enables movement.
Step-by-step explanation:
Function and Formation of Epithelial Tissue
The structure that covers surfaces, lines hollow organs, cavities and ducts, and forms sheaths is known as epithelial tissue, or epithelium. Its function is to provide a protective barrier, regulate permeability, and create a surface for absorption and excretion. When gland cells sink below the surface, they form glands which then have the function of secreting hormones or other substances necessary for the body's functions. These glands can be exocrine, secreting their substances into ducts, or endocrine, releasing their substances directly into the bloodstream.
The levels of organization of the human body range from cells to tissues to organs and finally to organ systems. Epithelial tissue covers the body’s surface and lines various cavities and passageways. It is made of closely packed cells, which form flat sheets to effectively protect and enclose structures underneath.
The skeletal system provides structural support, protects vital organs, and aids in movement, facilitated by muscles, which is the organ system that allows for the body's movement. Form and function in human cells are closely related, as the shape and structure of a cell directly influence its role in the body. For example, red blood cells are shaped to optimize their primary function of transporting oxygen.
Epithelial and muscle tissues exhibit key differences. Epithelial tissue forms protective coverings and sometimes glandular functions, whereas muscle tissue is responsible for movement. There are three types of muscle tissue: skeletal, smooth, and cardiac, each designed for specific functions within the body.