What is the difference between sebaceous and sweat glands?
Sebaceous glands, or holocrine glands, are found over the entire surface of the body except for the palms, soles, and dorsum of the feet. They are the largest and most concentrated in the face and scalp where they are the sites of origin of acne. The normal function of sebaceous glands is to produce and secrete sebum, a group of complex oils that include triglycerides and fatty acid breakdown products, wax esters, squalene, cholesterol esters, and cholesterol. Sebum lubricates the skin to protect it against friction and makes the skin more impervious to moisture.
Sweat glands, or eccrine glands, are found over the entire surface of the body except for the vermillion border of the lips, the external ear canal, the nail beds, the labia minora, and the glans penis and the inner aspect of the prepuce. They are most concentrated in the palms and soles and the axillae.
Each gland consists of a coiled secretory intradermal portion that connects to the epidermis via a relatively straight distal duct. The normal function of the sweat gland is to produce sweat, which cools the body by evaporation. The thermoregulatory center in the hypothalamus controls sweat gland activity through sympathetic nerve fibers that innervate the sweat glands. Sweat excretion is triggered when core body temperature reaches or exceeds a set point.