9/30/2014
1
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?
9/30/2014
2
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.
9/30/2014
3
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.
9/30/2014
4
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!