What is hair?
A: Hair is a protein filament that grows from follicles found in the dermis.
Hair is one of the defining characteristics of what?
A: Mammals.
The human body, apart from areas of glabrous
skin, is
covered in what?
A: Follicles which produce thick terminal and fine vellus hair.
Most common interest in hair is focused on what?
A: Hair growth, hair types, and hair care,
Hair is also an important biomaterial primarily
composed of what?
A: Protein, notably alpha-keratin.
Attitudes towards different forms of hair, such as
hairstyles and hair removal, vary widely across different what?
A: Cultures and historical periods.
Hair is often used to indicate a person's personal
beliefs or social position, such as what?
A: Their age, sex, or religion.
The word "hair" usually refers to what two distinct
structures?
A: The part beneath the skin, called the hair follicle and the hair shaft,
which is the hard filamentous part that extends above the skin surface.
The follicle is located in the dermis and does what?
A: Maintains stem cells, which not only re-grow the hair after it falls out,
but also are recruited to regrow skin after a wound.
A cross section of the hair shaft may be divided
roughly into how many zones?
A: Three.
Each strand of hair is made up of what?
A: The medulla, cortex, and cuticle.
The cortex, or second of three layers of the hair, is
the primary source of what?
A: Mechanical strength and water uptake.
The cortex contains melanin, which does what?
A: It colors the fiber based on the number, distribution, and types of
melanin granules.
The shape of the follicle determines what?
A: The shape of the cortex, and the shape of the fiber is related to how
straight or curly the hair is.
People with straight hair have round what?
A: Hair fibers.
Oval and other shaped fibers are generally more what?
A: Wavy or curly.
The cuticle is what?
A: The outer covering.
Its complex structure slides as the hair swells and is
covered with a single molecular layer of what?
A: Lipid that makes the hair repel water.
The glands at the opening of the hair produce a fatty
secretion that does what?
A: Lubricates the hair.
Where does hair growth begin?
A: Inside the hair follicle.
The only "living" portion of the hair is found where?
A: In the follicle.
The hair that is visible is the hair shaft, which
exhibits no what?
A: Biochemical activity and is considered "dead".
The base of a hair's root (the "bulb") contains the
cells that produce what?
A: The hair shaft.
The arrector pili muscles are responsible for causing
hairs to do what?
A: To stand up.
In humans with little body hair, the effect results in
what?
A: Goose bumps.