lip (labium oris)

Thin skin lines the external surface of the lip. The epidermis exhibits stratified squamous keratinized epithelium with desquamating layer. Beneath the epidermis is dermis with sebaceous glands associated with hair follicles and the simple tubular sweat glands. The core of the lip contains striated skeletal muscle, the orbicularis oris. The internal oral surface is lined by the stratified squamous nonkeratinized epithelium, that is thicker than epidermis. Deeper connective tissue contains mucus-secreting labial glands. Ducts of these glands open to the oral cavity. The connective tissue of the lip also contains adipose cells, nerve fibres, blood vessels. Stained: modified green trichrome (collagen tissue is green, muscle tissue is red, elastic fibres and nuclei of cells are black) Author: Mgr. Tereza Blassová, Ph.D. Scaning of the specimen: Mgr. Yaroslav Kolinko, Ph.D.