sebaceous gland

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

More about the experts All content is checked by medical journalists.

The sebum gland (Glandula sebacea) is a gland that occurs all over the body and is located in the dermis (corium) and is largely bound to hair. The sebum gland opens into the covering of the hair (hair follicle or hair follicle) and releases its fatty secretion to the surface of the skin. Read everything you need to know about the sebum!

What is the sebum gland?

The sebum is an exocrine gland, which means that it releases its secretion to the outside. The gland body consists of large sebum cells that are filled with fat droplets. With regrowing cells that are produced from below (by the basement membrane), the upper cells are pushed further and further towards the surface of the skin until they can no longer be nourished. In their innermost area, these cells then completely dissolve and reach the surface of the skin as fat paste via the hair follicle - most sebum glands each form a unit with one hair. There they coat the skin and hair with sebum, a thin, protective layer of fat that prevents it from drying out. The sebum also serves to protect against skin diseases, pathogens and chemicals.

Sebum glands are so-called holocrine glands, the secreting cells of which completely disintegrate while they release their secretion. From below, they are replaced by new cells.

Where are most of the sebum glands located?

There are a particularly large number of sebum glands on the scalp, on the nose, on the ear, in the genital area, in the T-zone (on the face) and in the front and rear sweat troughs on the torso.

Free sebum glands

In addition to the sebum glands that are bound to hair, there are also free ones that are not bound to hair. These occur wherever the skin merges into the mucous membrane, for example on the lips, on the nostril, on the upper eyelid of the eye, on the anus, on the glans and foreskin of the penis, on the labia minora, as well as on the nipple and areola.

Areas free of sebum glands on the body

There are only a few places on the body where there are no sebum glands. These are the palm of the hand, the soles of the feet and the extensor sides of the nail limbs.

What is sebum?

Sebum is the skin fat that arises from the sebum cells and is secreted on the surface of the skin. The sebum consists of a mixture of triglycerides, free fatty acids, waxes, squalene (hydrocarbons) and proteins as well as a small part of cholesterol.

The production of sebum is under hormonal influence, whereby testosterone (the male sex hormone) and progesterone (a steroid hormone that plays a role in the biosynthesis of sex hormones) stimulate production. In contrast, estrogens (female sex hormones) can inhibit sebum production.

What problems can a sebaceous gland cause?

A backlog of the secretion in the ducts leads to the so-called blackheads (comedones).

In acne vulgaris, the sebum glands are inflamed. When the inflammation spreads down along the follicles, acne conglobata occurs.

Hyperplasia, i.e. overdevelopment of a sebum gland, which can occur particularly in older people, manifests itself in a yellowish, centrally indented nodule. Such hyperplasias develop especially on the forehead.

An increased flow of sebum is called seborrhea. It occurs mainly in young people. Reduced sebum production is known as sebostasis. External influences such as UV light, cosmetics, oil and chlorine influence the activity of a sebum gland.

Tags:  pregnancy teenager drugs