The mucosa is a moist tissue layer that lines various cavities and organs in the body, including the mouth, nose, throat, and digestive tract. It serves several important functions, such as protecting underlying tissues, absorbing nutrients, and secreting mucus, which helps keep surfaces moist and traps pathogens. Mucosa is composed of epithelial cells, connective tissue, and a thin layer of muscle. Different types of mucosa can be found in different areas of the body, each adapted to its specific function. For example, the intestinal mucosa is specialized for nutrient absorption, while the respiratory mucosa helps filter and humidify the air we breathe.