Sebum and sweat both are our body secretions and they are secreted by their special type of glands. Sweat is produced by sweat glands and sebum is produced by sebaceous glands. Both are present in the layer of skin and both sebum and sweat producing glands are present mostly near hair follicles. Somehow similar to each other still differ in many aspects like, in the type of secretions for example; sebum is mostly made up of oily or waxy substance while sweat consist of water and sodium chloride. Both of the secretions help to maintain body temperature.
What is Sweat?
Sweat is produced by sweat gland which is also called an apocrine gland, a type of exocrine gland. Apocrine has coiled tubules and a duct which help to excrete the secretions of the gland near to the hair follicle. These glands are present near the junction of subcutaneous fat and dermis. Sweat producing glands are found in specific regions of the body like armpit, areola, nipples, eyelids, ear canal, nostrils, external genitalia and perianal region. The secretions of apocrine gland is periodic and the gland secretes oily fluid rich in lipids, steroids and proteins. Sweat maintains the temperature of the body and also excretes waste products through skin. Sweat is watery in nature made up of water, carbohydrates, proteins, waste material and sodium chloride. Sweat initially is odorless but as soon as it comes in contact with bacteria it starts producing odor. Sweat is mild acidic in nature having pH of 6-7.5. Human fetus of 5 months have sweat gland distributed all over his body which after birth become localized to specific regions like armpits, areola, perianal and external genitalia.
What is Sebum?
Sebum is produced by sebaceous glands which are microscopic holocrine glands, a type of exocrine gland present in the epidermis. Sebum helps in lubrication and in controlling the temperature. It also waterproof the skin and hair. Sebaceous glands are present on all parts of our body especially on face and scalp. But our palms and soles lack sebaceous glands. Sebaceous glands which are present on different parts of our body have different names like areolar glands that surround nipples, meibomian gland which are present on eyelids and Fordyce spots on cheeks, gum and lips. Sebaceous glands are found in hairy regions of the body where their excretory ducts are connected to hair follicles. Sebaceous glands which are connected to hair follicles are termed as pilosebaceous unit. Pilosebaceous unit consist of hair, hair follicle, arrector pilli muscle and sebaceous gland. Sebum is made up of wax esters, triglycerides, squalene and fat producing metabolites. Wax and squalene are only secreted by sebaceous glands of our body. Like sweat, sebum is also initially odorless and when it comes in contact of bacteria it produces odor. Sebaceous glands of human fetus during the last 3 months starts producing a protective covering called vernix caseosa. Vernix caseosa, a waxy layer that surrounds the fetus and protects it from amniotic fluid.
- Sweat is produced by apocrine gland while sebum is produced from holocrine gland. Apocrine and holocrine both are the types of exocrine gland.
- Sweat is composed mainly of water, salts and waste products while sebum is oily and waxy in nature.
- Sweat helps in thermoregulation of the body while sebum produces a lubricating and oily layer which decrease water evaporation and helps to combat dehydration.
- Sweat glands are present only in specific regions of the body like eyelids, ear, armpits, areola and external genitalia while sebaceous gland are present throughout the body except palms and soles.