Hair is made up of a certain type of protein known as keratin. As
with any part of our body, hair has several parts that make up its
biology. One strand of hair consists of a hair shaft the part that
is visible and grows above the skin, and the follicle the part from
which the root of the hair
grows and is located below the epidermis. The hair bulb, which
is a small but important part of the hair, produces the hair's color
pigment and is located at the end of the follicle.
Hair biology: the structure and functions of the different parts of hair
The hair follicle is made up of
different layers with different functions. The papilla, located
at the base of the follicle, contains capillaries that feed the
cells. The bulb, the hair's living part, is located at the lower
end of the follicle. The bulb is the only part of the hair that
is fed by the capillaries.
Two sheaths surround the hair follicle. The sheaths protect the growing hair shaft. The inner sheath covers the hair shaft and ends just below the opening of the oil glands. The outer sheath covers the hair shaft and continues up to the oil glands. The erector pili, a muscle that attaches the gland to the outer sheath, when contracted makes the hair on your skin stand up producing goose bumps.
Hair shafts are made up of dead protein called keratin. This hard protein comes in three layers. These layers are the medulla or inner layer, the cortex, and the cuticle or outer layer. The hair shaft is made up mostly of the cortex. The cuticle is made up of scales similar in structure to roof shingles.
Skin and Hair
The part of hair we see growing on our skin and scalp is the hair
shaft. The follicle and the root of the hair are located just below
the skin. One of the largest organs in the human body; the skin
is often overlooked in terms of an individuals health and welfare.
The skin has a wide range of functions, some of these functions
- Provide a flexible support and protection for the bodys underlying
organs and tissues
- Sweat glands in the skin provide a way for removing waste materials from the body
- Provide a way to feel sensations such as temperature, pain and pressure
- Protection from ultra violet light
- The skin also acts together with hair in preventing heat loss. Skin
and hair maintain the bodys temperature through trapping air,
providing an insulating layer for the skin.
The importance of hair and skin has gone beyond the typical biological
functions and purposes. Aside from the health related functions
of hair and skin, both parts of the body are also big considerations
when it comes to cosmetics. Hair and skin have become major parts
in an individual's declaration of uniqueness and individualism through
different hair styles,
colors and even skin piercings.