Sebaceous Gland - Locations and Morphology

Locations and Morphology

A branched type of acinar gland, the sebaceous glands exist in humans throughout the skin except in the palms of the hands and soles of the feet. Sebaceous glands can usually be found in hair-covered areas, where they are connected to hair follicles (see image at top). The glands deposit sebum on the hairs, and bring it to the skin surface along the hair shaft. The structure consisting of hair, hair follicle, arrector pili muscle, and sebaceous gland is known as a pilosebaceous unit. Sebaceous glands are also found in non-haired areas (glabrous skin) of eyelids, nose, penis, labia minora and nipples. Here, the sebum traverses ducts that terminate in sweat pores on the surface of the skin. At the rim of the eyelids, meibomian glands are a specialized form of sebaceous gland. They secrete a form of sebum (called (meibum)) onto the eye, slowing the evaporation of tears.