Sebaceous gland
Sebaceous glands are usually attached to hair follicles and release a fatty substance, sebum, into the follicular duct and to the surface of the skin. The glands are distributed over the entire body with the exception of the palms of the hands and the soles of the feet; they are most abundant on the scalp and face.The sebaceous gland secretes a mixture of fats (triglycerides, wax esters, squalene, and cholesterol) and cellular debris, which is discharged as sebum through the sebaceous duct connecting the gland to the hair follicle. Sebum helps to form the slightly greasy surface film of the skin; it thus helps keep the skin flexible and prevents the skin’s loss of absorption of excessive amounts of water.