Hair and Scalp Properties

A comprehensive set of fill-in-the-blank practice flashcards covering hair root anatomy, hair shaft layers, chemical composition, COHNS percentages, and polypeptide side bonds based on cosmetology notes.

Analyzing the hair and scalp is a key first step to providing services that maintain their health and __________.

integrity

The study of hair, including its diseases and care, is known as __________.

trichology

The word trichology comes from the Greek words trichos, meaning hair, and ology, meaning __________.

the study of

The hair, skin, nails, and glands are all part of the __________ system.

integumentary

A strand of human hair has two main parts: the hair root located below the epidermis and the hair __________ that projects above the epidermis.

shaft

The living portion of hair found below the skin consists of the hair follicle, hair bulb, and __________.

dermal papilla

The tube-like structure in the skin or scalp that surrounds the hair root and anchors the hair in the skin is the hair __________.

follicle

Hair follicles are not found on the palms of the hands or the soles of the __________.

feet

The living, bulb-shaped structure located at the base of the hair follicle is the hair __________.

bulb

The cone-shaped elevation at the base of the hair bulb that contains blood vessels supplying nutrients is the __________.

dermal papilla

The involuntary muscle in the dermis that contracts to cause goosebumps is the __________ muscle.

arrector pili

Sebaceous glands produce an oily substance called __________ that lubricates the hair and skin.

sebum

The nonliving portion of hair that extends beyond the skin or scalp is called the hair __________.

shaft

The hair shaft consists of three main layers: the cuticle, cortex, and __________.

medulla

The outermost layer of the hair shaft, which consists of overlapping cells like shingles on a roof, is the __________.

cuticle

During chemical services, the hair cuticle softens and __________ to allow chemicals to penetrate the cortex.

swells

The fibrous protein layer responsible for hair's strength, elasticity, and color is the __________.

cortex

The cortex contributes to about __________ of hair's weight.

$$90\%$$

The inner core or pith of the hair strand, which is always present in beard hair but generally absent in fine hair, is the __________.

medulla

Hair is composed primarily of a fibrous protein called __________.

keratin

During keratinization, newly formed cells mature, fill up with keratin, move upward, lose their __________, and die.

nucleus

Hair is composed of approximately __________ protein.

$$90\%$$

The five major elements that make up human hair are Carbon, Oxygen, Hydrogen, Nitrogen, and Sulfur, referred to as the __________ elements.

COHNS

In an average hair strand, Carbon makes up __________ of its composition.

$$51\%$$

In an average hair strand, Oxygen makes up __________ of its chemical composition.

$$21\%$$

In an average hair strand, Hydrogen makes up __________ of its chemical composition.

$$6\%$$

In an average hair strand, Nitrogen makes up __________ of its chemical composition.

$$17\%$$

In an average hair strand, Sulfur makes up __________ of its chemical composition.

$$5\%$$

Amino acids are joined end to end by strong chemical bonds called __________ bonds, also known as end bonds.

peptide

Polypeptide chains exist in a spiral configuration called a __________.

helix

The cortex side bonds account for about __________ of hair's overall strength.

$$\frac{1}{3}$$

A weak physical side bond formed by the attraction of opposite charges and easily broken by water or heat is a __________ bond.

hydrogen

A weak physical side bond that is broken by changes in pH (strong alkaline or acidic solutions) is a __________ bond.

salt

A strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids is a __________ bond.

disulfide

Disulfide bonds broken by hydroxide relaxers are converted to __________ bonds.

lanthionine

Many thermal tools reach temperatures up to __________ ($232\,^\circ\text{C}$), which can weaken hair protein.

$$450\,^\circ\text{F}$$

Strong chemical peptide end bonds are broken by chemical __________ and cause the hair to dissolve.

depilatories