The five elements—carbon, oxygen, hydrogen, nitrogen, and sulfur—that make up human hair, skin, tissue, and nails.

Outermost layer of hair; consisting of a single, overlapping layer of transparent, scale-like cells that look like shingles on a roof.

The brief transition period between the growth and resting phases of a hair follicle. It signals the end of the growth phase.

Lowest part of a hair strand; the thickened, club-shaped structure that forms the lower part of the hair root.

Strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids to create one cystine, which joins together two polypeptide strands like rungs on

a ladder.

The part of the hair located below the surface of the epidermis.

Units that are joined together end to end like pop beads by strong, chemical peptide bonds (end bonds) to form the polypeptide chains that comprise proteins.

Units that are joined together end to end like pop beads by strong, chemical peptide bonds (end bonds) to form the polypeptide chains that comprise proteins.

Also known as growth phase; phase during which new hair is produced.

Vellus hair is also known as _____ hair.

Hair is composed of protein that grows from cells originating within the _____.

The body naturally produces _____ of the 20 amino acids that make up hair.

A weak, physical, cross-link side bond between adjacent polypeptide chains that is broken by changes in pH is a _____ bond.

What are the three growth cycles of human hair?

What substances are comprised of long, coiled, complex polypeptides made of amino acids?

A lengthwise section of hair shows that cuticle scales overlap and each individual cuticle scale is attached to the _____.

The pocket or tube-like depression in the scalp or skin that contains the hair root is the hair _____.

The three different types of side bonds that link chains of amino acids together are _____.

A physical side bond that is easily broken by water and heat is a _____ bond.

A small, cone-shaped area located at the base of the hair follicle that fits into the hair bulb is the _____.

Which type of hair has the largest diameter and usually requires more processing?

What part of the hair is located below the surface of the epidermis?

The hair shaft that emerges from the scalp is a nonliving fiber composed of _____.

What structures contain the blood and nerve supply that provide the nutrients needed for hair growth?

The small, involuntary muscle fiber in the base of the hair follicle is the _____.

What is the oily substance secreted by the skin’s oil glands that lubricates the hair and skin?

The Greek word trichos means _____.

What type of hair is short, fine, unpigmented, and downy?

What term refers to the scientific study of hair and its diseases and care?

Hair is approximately _____ percent protein.

The units of structure that build protein and are joined together end to end like pop beads are _____.

A long chain of amino acids linked by peptide bonds is called a _____ chain.