Sebum refers to an oily substance secreted by the sebaceous glands in the skin of mammals. Its main purpose is to make the skin as well as hair waterproof besides keeping them from drying out. Excessive sebum, however, tends to make the skin or hair oily, which can begin to smell when it is broken down by bacteria outside the body. The sebaceous glands are generally attached to hair follicles, but they can even exist in some hairless areas of the human body, such as the eyelids, where they add sebum to tears in order to keep the eye moist.
Sebum
Sebum, as well as the sloughed skin cells, makes up the waxy vernix caseosa which covers newborn babies. Without this coating, babies would have come out of the womb very wrinkled due to the wet environment of the womb. Sebaceous glands tend to go into overdrive during puberty which causes oily skin, odours, as well as acne. As people age a lessening of the sebum levels leads to dry skin which can accelerate the formation of wrinkles.
Sweating
Sweating refers to the body’s natural way of cooling. We sweat to keep the body at its normal temperature of 98.4 degrees Fahrenheit (37 degrees Celsius).
The food that we eat everyday has to be burned off. This burning of this food produces heat within the body which triggers our brain to kick start the natural cooling process of the body. Inside the human body are long, twisting tubes of cells which are known as the sweat glands. The blood vessels in our skin open and the fluid gets released through our pores.
There are nearly 2 million sweat glands in our body. We may not know it but we perspire even when it is cold and we are not doing anything strenuous. The body is two-thirds water and we tend to lose a great amount of this every day through sweating. Thus it is very important to drink a lot of water each day to replenish the lost fluids.
There are two different types of sweat glands, which are the Eccrine and the Aprocrine glands. The Eccrine is more common of the two. It is found in parts of the body like the forehead, palms of the hands as well as the soles of the feet. The Aprocrine can be found in the armpits as well as the end of the hair follicles.
Sweat itself is made up of various elements. The most common elements are water and sodium, which when combined is known as salt. At times, we can have a low sweat production, in case it is cool or we are resting. Higher sweat production occurs in hot weather or while exercising. High sweat production will have about 20 percent more sodium than low sweat production.
Perspiration produced through the Aprocrine glands or in the armpit, is thicker and may even have a yellowish colour. This is because it contains proteins as well as fatty acids. This type of sweat under the arms, coupled with antiperspirants, can tinge clothing yellow. We apply deodorants to the armpits only, in order to counteract the smell of the Aprocrine sweat. Sweat is actually odourless, but when it begins to decompose and is attacked by bacteria, the smell can get unpleasant.
Sweating, which is at times embarrassing, is a natural bodily function which is crucial to our survival.