Question

Write name of oily substances found in sebaceous glands.

Answer 1

Hint: Sebaceous gland is an oil secreting gland. It is an exocrine gland present in the skin. It opens into the hair follicle and produces oil and waxy matter. The secretion is essential for the lubrication of hair and skin of the mammals.

Complete answer:
Sebaceous gland is an exocrine gland which secretes oily or waxy matter which lubricates the hair and skin. In human beings’ sebaceous glands are mostly found on the face and scalp. It is also found in palms, hands, soles and feet.
Sebaceous gland produces a secretion called the Sebum. The sebum is composed of wax, triglycerides, squalene and free fatty acid. The sebum is composed of sapienic acid which is a fatty acid and is only found in humans. The sebum is odorless but the bacterial action produces strong odors. The secretion of sebum is affected by androgens and testosterone. They increase the secretion of sebum. The estrogens inhibit the secretion of sebum.

Function of Sebum:
1)Thermoregulation- Sebum plays a vital role in thermoregulation. In hotter climates it helps in emulsification of sweat and prevents dehydration whereas in cold climates the sebum becomes more lipid like which coats the hair and skin and protects the body from cold.

2)Sebum protects the body against microorganisms as it is slightly acidic in nature and forms a barrier.

3)It supplies vitamin E to the skin.

Note: The meibomian gland in the eyelids produces a type of sebum which lubricates the eye and slows the evaporation of tears. Ear wax is also composed of sebum. The sebum is responsible for producing skin diseases like acne.