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Accessory Organs of Skin

Hair follicles

1. Epidermal cells at base give rise to hair

2. Hair: dead, keratinized epidermal cells

arranged in scale-like fashion

3. Arrector pili muscle: smooth muscle attached

to each follicle (causes goose bumps)

4. Hair color determined by epidermal

melanocytes

What shape is your hair

shaft?

Oval: hair is smooth, silky and wavy

Flat & Ribbonlike: hair is curly or kinky

Perfectly round: hair is straight & tends

to be course

Where hair is not found

Palms of hands

Soles of feet

Nipples

Lips

Why does hair turn

gray/white?

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Did you know?

Humans have more hair than apes.

Although theirs is thicker, longer, and

typically darker.

Challenge Question!

The hair in your ears, nose, and around

your eyes play important roles in keeping

you healthy….Can you explain why?

Gland review (Do Not Write!)

1) Exocrine: secretes product into a duct that

opens into an internal or external surface A) Merocrine: releases fluid products through cell membranes

B) Apocrine : lose small portions of cells during secretion

(mammary, certain sweat glands)

C) Holocrine: entire cells filled with secretory product

(sebaceous glands)

2) Endocrine: secretes products into tissue fluid

or blood (pituitary, adrenal, thymus, etc.)

Glands Galore!

Sebaceous glands - Holocrine

Sebaceous glands are located near

the hair follicle and produce sebum

- the natural oil of your skin.

Sebum = a mixture of different

waxes and fats

Facial skin contains ~ 3,000 of these

glands per square inch.

Sweat Glands

Sweat : water, salt, waste (N cmpds)

Apocrine glands -Merocrine

Located - armpit, belly button, genital and

anal areas

Activated at puberty, secretes by hair follicle

Situated deep within the dermis & produce a

milky type of sweat, causing body odor when

bacteria breaks it down on the epidermis.

Eccrine glands - Merocrine Do not use the hair follicle to exit sweat to the skin,

each has its own dedicated pore.

Sweat glands regulate body temperature, by drawing

heat away from the body.

Eccrine sweat is also helpful in eliminating waste salts

from the body.

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1 Square inch if Skin

Contains…

What makes these hairs stand on

end? Why?

Can you name

structures 1-4?

Nails

Your nails extend from the epidermis and contain keratin.

Stratified squamous epith.

Cell division occurs in nail root

They play an important role in

Grasping objects

Scratching

Protecting fingers and toes.

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A. Nail plate E. Matrix

B. Lunula F. Nail Bed

C. Root G. Hyponychium

D. Sinus H. Free margin

Did you Know?

Your fingernails grow about 5 times

faster than your toenails!