Name 5 skin appendages.

Hair
Hair follicles
Nails
Sweat glands
Oil glands

What is the main function of body hair?

To sense insects before they bite or sting.

What are three reasons for having hair on your head?

Guards against head trauma, heat loss, and sunlight

What are flexible strands produced by hair follicles?

Hairs

What is another word for hairs?

Pili

What are the chief regions of the hair?

The shaft and root

In the shaft, keratinization is ________, but in the root, keratinization is ________.

Complete...
Still ongoing

What are the three concentric layers of keratinized cells in a hair?

Medulla, cortex, cuticle

Which of the three is absent from fine hairs?

The medulla

The _______ consists of large cells and airspaces.

Medulla

What's the bulky layer surrounding the medulla?

The cortex

The ________ is formed from a single layer of cells overlapping one another.

Cuticle

When the cuticle wears away at the tip of the hair shaft, allowing keratin fibrils in the cortex and medulla to frizz out. This is called a ________.

Split end

Hair pigment is made by _______ at the base of the hair follicle, and transferred to the cortical cells.

Melanocytes

How is red hair colored?

By an iron-containing pigment called trichosiderin

When melanin production decreases, and air bubbles replace melanin in the hair shaft, the hair ________.

Turns gray (or white)

________ fold down from the epidermal surface into the dermis.

Hair follicles

The deep end of the follicle expands to form a ________.

Hair bulb

A knot of sensory nerve endings is called a ________.

Hair follicle receptor

A hair follicle receptor is also called a ________.

Hair root plexus

A hair follicle receptor or hair root plexus wraps around each _______.

Hair bulb

________ is a nipplelike bit of dermal tissue that protrudes into the hair bulb.

Hair papilla

What supplies nutrients to the growing hair and signals it to grow?

Papilla

The wall of the hair follicle is composed of what 3 things?

The outer peripheral connective tissue sheath
The inner epithelial root sheath
A glassy membrane

The actively dividing area of the hair bulb that produces the hair is the ________.

Hair matrix

The hair matrix originates from the _____ _____.

Hair bulge

The two classifications of hair are:

Vellus
Terminal

The coarse, longer hair is ________, and pale, fine hair is _________.

Terminal...
Vellus

Terminal hairs of puberty grow in response to the effects of ________.

Androgens

What is excessive hairiness called?

Hirsutism

Hair thinning and some degree of baldness is called ________.

Alopecia

________ is when the immune system attacks the follicles and the hair falls out in patches.

Alopecia areata

The white crescent of the nail is called:

Lunule

The borders of the nails are overlapped by skinfolds called ________.

Nail folds

The fold that projects onto the body is the ________.

Cuticle

The thickened region beneath the free edge of the nail is the ________.

Hyponychium

Sweat glands are also called ________.

Sudoriferous glands

How many sweat glands does the average person have?

Up to 3 million

What are the two types of sweat glands?

Eccrine
Apocrine

Eccrine sweat glands are also called _______.

Merocrine sweat glands

Sweat is 99% ________.

Water, salts, vitamin C, antibodies, dermcidin, and traces of metabolic waste.

Sweat is _______, with a Ph between ___ and ___.

Acidic...
4 and 6

________ glands begin functioning at puberty and play little role in maintaining a constant body temp.

Apocrine

Modified apochrine glands found in the lining of the external ear canal

Ceruminous

Oil glands are also called ________ glands.

Sebaceous

True or False:
Sebaceous glands are also found in the thick skin of the palms and soles.

False
Sebaceous glands are found all over the body except the thick skin. Eccrine glands are particularly abundant on the palms and soles.

Sebaceous glands produce an oily substance called ________.

Sebum

Overactive sebaceous glands can cause ________ in infants. This is also called _______.

Seborrhea...
Cradle cap