Mucosa is a thin, protective layer of tissue that lines the inner surfaces of many parts of your body, including hollow organs and body cavities. It forms an important barrier between the inside of your body and the outside environment, helping to protect against infection, injury, and irritation. If the mucosa becomes damaged, germs such as bacteria or fungi can enter the body and cause infections or inflammation.
Not all mucosal surfaces are the same. They are lined by different types of specialized cells depending on their function and location in the body. For example, the mucosa in your mouth and throat is covered by flat, protective cells called squamous cells that help resist injury from food or other materials. In contrast, the mucosa lining your stomach and intestines is made up of specialized glandular cells that form structures called glands. These glands produce mucus, digestive enzymes, and other substances important for digestion and protecting the tissue beneath.
Mucosa lines many different organs and structures throughout your body, including:
Inside your mouth, throat, and nasal cavity.
Surface of your eyes (conjunctiva).
Esophagus (the tube connecting your throat to your stomach).
Stomach.
Small intestine.
Large intestine (colon).
Bladder and urinary tract.
Respiratory passages (such as your airways and lungs).
Reproductive organs (such as the uterus, cervix, and vagina).
When mucosal tissue is damaged, it can no longer effectively perform its protective function. This can allow harmful germs or irritating substances to enter the body, leading to infections or inflammation. Conditions such as ulcers, infections, or chronic inflammation can occur when the mucosa becomes injured or irritated repeatedly over time.
Many common types of cancer start from the cells found within mucosal tissue. These cancers are collectively called carcinomas. The specific type of carcinoma depends on the cells involved:
Squamous cell carcinoma starts from mucosa lined by squamous cells, such as the mouth, throat, cervix, and esophagus.
Adenocarcinoma starts from glandular cells found in mucosal tissue, such as those lining the stomach, intestines, colon, and certain areas of the lungs and reproductive organs.
Recognizing where a carcinoma originated helps your doctor select the most effective treatment options for your specific type of cancer.