The Sebaceous Glands
Sebaceous Gland (Oil Gland) and Sebum
This is the microscopic oil gland in the skin that secretes a waxy, oily substance called sebum onto and along the hair follicle. It lubricates and waterproofs the skin and hair. Sometimes the glands may become hyper and/or over active, especially in adolescents, and produce excess sebum. This can cause skin conditions like :
Ectopic Sebaceous Glands
Sebaceous Gland Carcinoma
Sebaceous Gland Hyperplasia
The gland's body density differ from site to site on the human body. The highest being the face and scalp, followed by the back, chest, abdomen, arms and legs.
However, the number of oil glands remain approximately the same throughout life, while its size tends to increase with age.
The human oil glands show a similarity in structure and secrete sebum by a holocrine process.
Sebum (Natural Oil) - What is it?
This is the body's natural oil or skin oil that secrets from the sebaceous glands, typically located at or near the root of every hair follicle.
This natural skin oil makes the skin soft and waterproof. It prevents the skin from turning dry, cracking and getting brittle. As a natural lubricant, it keeps the hair and skin moisturised.
The gland secretion provides Vitamin E to the upper layers of the facial skin.
Ever wondered why the skin can be so dry or oily?
Oily skin, flaky scalp, acne and dry skin can all be linked to the production of, or lack of production of, sebum from the oil glands.
The composition and lipid content of sebum in humans is as follows:
% composition and Substance
16% free fatty acids
25% wax monoesters
Sapienic acid is a sebum fatty acid that is unique to humans. While wax esters, like squalene, are unique to sebum and not produced anywhere else in the body.
Sebum also contains 45% non-water-soluble fatty acids known to have broad antimicrobial activity.
It is also odourless, but its bacterial breakdown can produce odour.
The androgen stimulated oil glands will produce more sebum. This amasses within the hair follicles as it travels up the whole length of the hair shaft where it blends in with the bacteria (Propionibacterium Acnes), normal skin and lifeless follicular pores and skin cells.
The lifeless skin cells usually get pushed or forced to the skin surface where they are ejected.
The over production of sebum may result in an increased chance of clogged follicles that potentially result in acne breakouts and vice versa.
The oil gland's development or function in the fetal or neonatal cycles appear to be controlled by endogenous steroid synthesis and by maternal androgens as well as by other morphogens.
The most evident purpose of the glands is to expel sebum. Therefore, a substantial increase in sebum excretion develops a few hours following birth, this peaks during the initial week and gradually diminishes afterwards.
A fresh surge later in life develops at about age 9 with adrenarche and continues up to age 17 , when the adult level is reached.
However, hormonal acne does not only affect teenagers, it also affects adults. The start of acne may be triggered by the production of hormones called androgens.
The production of androgens energize the glands to produces more sebum and cause them to expand, especially when hormonal secretion, changes or imbalances occur.
Individuals who develop hormonal acne typically have over stimulated, overactive oil glands. The production of androgen generally enters into full force between the ages of 11 to 14 when most young boys and girls experience puberty.
Therefore, young boys and girls may have to live through hormonal changes during adolescence as well as shed more skin rapidly. With the increased output of sebum, lifeless skin cells stick together and eventually clog up the hair follicles.
Once the hair follicles are clogged up it transforms into a breeding ground for bacteria. This bacteria exists on human skin regardless of acne, it therefore, ingests sebum and produces a chemical that can cause inflammation in the follicle and surrounding skin.
Acne in younger ladies may be influenced by hormonal changes linked to endocrine imbalance, menstruation, stress, pregnancy, and ovarian disease.