Sebum and Sweat Glands

Sebum is an oily substance secreted by the sebaceous glands in mammalian skin. Its main purpose is to make the skin and hair waterproof and to keep them from drying out. Excessive sebum, however, can make the skin or hair oily, and can begin to smell when broken down by bacteria outside the body. The sebaceous glands are usually attached to hair follicles, but they can also exist in some hairless areas of the human body. The best example of this is the eyelids, where they add sebum to tears to keep the eye moist.Sebum, along with sloughed skin cells, makes up the waxy vernix caseosa that covers newborn babies. Without this coating, babies would come out of the womb very wrinkled from the wet environment of the womb. Sebaceous glands often go into overdrive during puberty causing oily skin, odors, and acne. As people age a lessening of sebum levels lead to dry skin and can also accelerate the formation of wrinkles.

Sweating

Sweating is the body's natural way of cooling us down. We sweat in order to keep the body at its normal temperature, which is 98.6 degrees Fahrenheit (37 degrees Celsius).

The food we eat everyday has to be burned off somehow. The burning of this food produces heat within the body which triggers our brain to kick start the body's natural cooling process. Inside the human body are long, twisting tubes of cells known as the sweat glands. The blood vessels in our skin open and the fluid is released through our pores.

There are approximately 2 million sweat glands in our body. We may not realize it but we perspire even when it is a cold day and we are not doing anything particularly strenuous. The body is two-thirds water and we lose a great amount of this every day through sweating. This is why it is so important to drink a lot of water each day in order to replenish the lost fluids.

There are two different types of sweat glands: the Eccrine and the Aprocrine glands. The Eccrine is the more common of the two and is found in parts of the body such as the forehead, palms of the hands and soles of the feet. The Aprocrine can be found in the armpits and the end of the hair follicles.

Sweat itself is made up of different elements. The most common elements are water and sodium, which combined are known as salt. At times, we can have a low sweat production--this happens when it is cool and we are resting. Higher sweat production occurs in very hot weather or when we are exercising. High sweat production contains about 20 percent more sodium than low sweat production.

Perspiration that is produced through the Aprocrine glands, or in the armpit, is thicker and might have a yellowish color. This is because it contains proteins and fatty acids. It is this type of sweat under the arms, coupled with antiperspirants, which can tinge clothing yellow. We only apply deodorants to the armpits, in order to counteract the smell of the Aprocrine sweat. Sweat is actually odorless, but when it starts to decompose and is attacked by bacteria, the smell can be unpleasant.

Sweating, although at times embarrassing, is a natural bodily function crucial to our survival.