A mucous membrane (plural - mucosae or mucosas; singular - mucosa; Latin - tunica mucosa) is a lining of mostly endodermal origin. It consists of an epithelium and an underlying lamina propria of connective tissue. The membranes line some body cavities that are exposed to the external environment and some internal organs. They are at several places contiguous with skin: at the nostrils, the lips of the mouth, the eyelids, the ears, the genital area, and the anus.
In the female, the glans clitoridis and the clitoral hood, and in the male, the glans penis (the head of the penis) and the inner layer of the foreskin, all have a mucous membrane. The urethra is also lined with a mucous membrane. Some mucous membranes are involved with absorption and secretion. The thick fluid secreted by some mucous membranes and/or associated glands is termed mucus. The mucus can be protective.
Some examples of mucosae