Major roles of the
Integumentary System






protection
maintenance of normal
body temperature
storage (of fat)
synthesis (of vitamin D)
excretion (of salts, water
and wastes in sweat)
sensory perception
The Skin: 3 Major layers
Did You
Know?...
 At 8-10
pounds, the
skin is bodies
largest organ!
The Epidermis
 The epidermis is the outer
layer of skin. The
thickness of the epidermis
varies in different types of
skin. It is the thinnest on
the eyelid at .05 mm and
the thickest on back at 1.5
mm.
 Cells of the epidermis are
constantly shedding off
and replacing
themselves…
Which layer of the epidermis is this?
The Dermis
 This layer varies in
thickness as well,
depending on the area
of the body. It is a mere
0.3 mm on the eyelid
and 3.0 mm on your
back.
 The dermis is
composed of tissue….
Dermis Tissue: Collagen
 Collagen is the most abundant and
important structural protein in your
body. It strengthens and supports
many body tissues from the outside
creating an “extracellular matrix.”
1 Square inch if Skin
Contains…
What makes these hairs stand on end? Why?
Layer 3: The Subcutaneous
 Also referred to as the
“hypodermis,” this layer of the
skin is composed primarily of
adipose tissue (fat). This layer
plays a key role in insulating the
body and regulating the
temperature of the skin.
 The hypodermis can vary
significantly in thickness and
incorporates larger blood vessels
and nerves.
Nails
 Your nails extend from the
epidermis and contain a
tough protein called
keratin. They play an
important role in grasping
objects, scratching, and
protecting fingers and
toes.
A. Nail plate; B. lunula; C. root; D.
sinus; E. matrix; F. nail bed; G.
hyponychium; H. free margin
Did you Know?
 Your fingernails grow about 5 times
faster than your toenails!
Hair
 Also composed of the
protein keratin hair
acts as an effective
insulator between you
and the environment.
 hair follicles originate
in the dermis.
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?
Did You Know?
 Hair can grow as
little as 0.1 inches
per month or as fast
as 0.5 inches per
month depending
on genetics and
your diet.
Damaging the Skin
Puncture wounds are caused by a sharp object that
penetrates the skin. Such wounds may cause
significant deep injury that is not immediately
recognized. These types of wounds do not bleed
freely
The most common type of open wound is a
laceration. Lacerations are commonly called
cuts and are an irregular cut or tear through
the skin.
Abrasions are commonly called scrapes. They
occur when the skin is rubbed across a rough
surface. Abrasions involve variable depths of skin.
An avulsion is a tearing away of body tissue.
Avulsions raise flaps of tissue, usually along
normal tissue planes. The avulsed part may
be totally severed from the body or it may be
attached by a flap of skin.
Disorders of the skin
•Lesions and tumors
•infections (bacterial, viral, fungal, parasitic)
•inflammatory reactions and allergies
•Genetic diseases
•acne
Anatomy of a Pimple