Simple epithelial tissue is a type of tissue that consists of a single layer of cells. This structure allows for efficient absorption, secretion, and filtration. Simple epithelial tissues are classified based on the shape of the cells, which can be squamous, cuboidal, or columnar. Each type serves specific functions in various organs and systems. These tissues line surfaces and cavities throughout the body, including the lungs, kidneys, and intestines. Their thinness facilitates the exchange of materials, such as gases and nutrients, making them essential for maintaining homeostasis. Simple epithelial tissues play a crucial role in protecting underlying structures while allowing for selective permeability.