ALL ABOUT THE
Created by Mark Lewis
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Created by Mark Lewis
INTRODUCTION TO THE INTEGUMENTARY
SYSTEM
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The integumentary
system consists of the
skin, hair nails and
exocrine glands.
Has three layers: the
epidermis, dermis, and
subcutaneous layer
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Created by Mark Lewis
THE SKIN
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The skin is the outer
covering of the body.
It protects the body from
chemicals, diseases, UV
rays, and physical harm.
It is the largest organ in
the body.
Two layers of the skin:
the epidermis and the
dermis.
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MODEL OF THE SKIN
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Created by Mark Lewis
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Created by Mark Lewis
THE EPIDERMIS
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The outermost layer of the skin; it covers almost the
entire body.
About 1/10 mm thick and consists of 40 or 50 rows of
simple squamous epithelial tissue.
Does not contain blood (avascular)
90% of the epidermis is made of keratinocytes, which
makes the skin tough, scaly, and water-resistant
Melanocytes configure about 8% of the epidermis; these
cells produce the brown or black pigment, melanin
Langerhans cells (cells that detect light and pathogens
entering the skin) and merkel cells(touch-sensing cells)
round out the composition of the epidermis.
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LAYERS OF THE EPIDERMIS
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Stratum basale- deepest layer,
contains the stem cells that
make all the other epidermal
cells
Stratum spinosum- contains the
langerhans cells and rows of
prickly keratinocytes
Stratum granulosum- location
where keratinocytes produce
waxy lamellar granules to
waterproof the skin
Stratum lucidum- made of dead
keratinocytes
Stratum corneum- outermost
layer, made of rows of dead
keratinocytes, this layer’s
purpose is protection.
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Created by Mark Lewis
THE DERMIS
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The dermis is the deep
layer of skin under the
epidermis.
Made of dense
connective tissue,
nervous tissue, blood,
and blood vessels
It is very thick, and it
gives the skin its
strength and elasticity.
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LAYERS OF THE DERMIS
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Papillary layer- outer layer,
contains finger-like extensions
called dermal papillae (increase
surface area); provide nutrients
and oxygen to the epidermis; its
nerve cells are used to sense
touch, pain, and temperature in
the epidermis
Reticular layer- thick and tough
deeper layer; made of dense
connective tissue, containing
collagen and elastic fibers;
contains blood vessels to support
the skin cells and nerves to sense
pressure and pain
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(subcutaneous layer)
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SUBCUTANEOUS LAYER
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Located under the dermis
Connects the skin,
muscle, and bones
Serves as fat storage
The areolar connective
tissue in this layer
contains elastin and
collagen fibers to allow
the skin to stretch.
The fatty adipose tissue in
this layer stores energy
and traps heat to insulate
the body.
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FUNCTIONS OF THE INTEGUMENTARY SYSTEM
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TEMPERATURE HOMEOSTASIS
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The skin regulates the body’s temperature.
During hypothermia, the smooth muscle in blood vessels
relaxes and allows more blood into the skin(vasodilation);
this pulls heat away from the core and radiates heat to the
outside of the body; sweat also transports water to the
surface of the skin, where it evaporates, absorbs heat, and
cools the body
During hyperthermia, the skin heats the body in two ways:
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The arrector pili muscles at the base of the hair follicle form
goosebumps by contracting, trapping air under hairs, and
insulating the body surface.
Vasoconstriction: smooth muscles in the walls of blood vessels
contract to restrict blood flow, keeping the body core warm
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HERE’S HOW IT WORKS!
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VITAMIN D SYNTHESIS
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Vitamin D is produced
when UV rays hit the skin.
The stratum basale and
the stratum spinosum
contain a molecule called
7-Dehydrocholesterol,
which produces vitamin
D3 when hit by UV rays
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The kidneys later convert
Vitamin D3 into Vitamin D
that can be used by the
body.
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SKIN PIGMENTATION
Melanin, the black or brown pigment, protects the
skin from UV rays and gives the skin and hair its
tan or brown color
 Melanin increases as UV light exposure increases.
 Carotene, a yellow or orange pigment, shows up in
a person with low melanin.
 Hemoglobin, a red pigment found in red blood
cells, also reveals itself in people with little
melanin as a light red or pinkish color
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CUTANEOUS SENSATION
The skin picks up touch, pain, pressure,
vibration, and temperature signals.
 Merkel disks in the epidermis and touch
corpuscles in the dermis sense the feel and
shape of objects.
 Lamellar corpuscles in the deep dermis detect
vibrations and pressure changes.
 Inside the dermis, there are loose nerve ends
that can sense pain and temperature changes.
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NOW ITS TIME FOR A COOL INTERACTIVE
ACTIVITY ON HOW THE SKIN WORKS!!!!!!!!!!!!!!!!!!!
Skin, Skin Information, Facts, News, Photos -National Geographic
 http://science.nationalgeographic.com/scienc
e/health-and-human-body/human-body/skinarticle.html
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ANCILLARY(ACCESSORY) ORGANS
NAILS
HAIR
SWEAT GLANDS
SEBACEOUS
GLANDS
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HAIR
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Hair is made of tightly
packed dead
keratinocytes.
It protects the body from
UV rays and insulates
the body.
Hair is made of three
parts: follicle, root, and
shaft.
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Follicle- a depression of
epidermal cells into the
dermis; place where
keratinocytes are made
Hair root- located within
the follicle and below
the skin’s surface
Hair shaft- part outside
of the skin and has
three layers (see next
slide)
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Created by Mark Lewis
LAYERS OF THE HAIR SHAFT
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Cuticle- outermost layer
made of keratinocytes,
which are stacked like
shingles
Cortex- the spindle-shaped
cells in the cortex contain
the pigments that give hair
its color and width
Medulla- although not
present in all hair, it
contains pigmented cells
full of keratin; when
absent, the cortex
continues through the
middle of the hair shaft
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Created by Mark Lewis
ANATOMY OF THE HAIR
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Created by Mark Lewis
NAILS
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Nails are made of sheets of hardened keratinocytes
They protect the ends of the digits, and they are used for
scraping and manipulating small objects.
Nails grow form a deep layer of epidermal tissue known as
the nail matrix, which surrounds the nail root.
The new cells formed by the nail matrix force the cells of the
nail root and body outward
The lunula is the white part at the proximal end where some
of the nail matrix is visible.
The eponychium is a layer of epithelium that covers the nail
body and seals the nail to prevent infection.
Lets go to the next slide to see the different layers and the
anatomy of a nail.
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THREE LAYERS/ANATOMY OF A NAIL
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2)
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Nail root- portion found
under the skin
Nail body- visible
portion of the nail
Free edge- the end
part of the nail that
has grown beyond the
end of the digit
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SWEAT(SUDORIFEROUS) GLANDS
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Sweat glands are exocrine glands
that are found in the dermis.
There are two types of sweat
glands:
Eccrine sweat glands- found in
most regions of the skin;
produce a water and sodium
chloride secretion; these glands
are used to lower the body’s
temperature
Apocrine sweat glands- found in
the axillar and pubic regions of
the body; the sweat produced by
these glands exits along the hair
shaft(ducts are located in the
follicle)
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SEBACEOUS GLANDS
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Exocrine glands in the
dermis that produce and oily
substance called sebum
Sebaceous glands are found
in all parts of the skin
except the palms and soles
of the feet.
Sebum is brought to the
surface of the skin by hair
follicles
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It also waterproofs and makes
the skin elastic
It lubricates and shields the
hair cuticles
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Created by Mark Lewis
CERUMINOUS GLANDS
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Special exocrine glands in
the dermis of the ear
canals
They produce a waxy
substance called
cerumen.
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Cerumen protects ear
canals and moistens the
eardrum
It also reaps foreign
substance in the ear canal
It’s made constantly and is
pushed to the outside of
the ear canal.
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COMMON SKIN DISEASES
Cold sores- red blister filled with
fluid around the mouth; caused
by the herpes simplex virus
Psoriasis- noncontagious skin disorder that
is characterized by scaly patches of skin
Vitiligo- condition in which there are white
patches on the skin due to loss of the
pigment, melanin
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MORE COMMON SKIN DISEASES
Shingles- disorder that occurs when the
chickenpox virus resurfaces and causes a
painful rash
Ingrown nail- occur when the edge of the nail
grows into the skin of the toe
Callus- place on the skin that has been
hardened due to constant friction
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Created by Mark Lewis
NOW FOR SOME FUN AND INTERESTING FACTS !!
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Did you know that an average person’s skin weighs 10
pounds and has a surface are of 20 square feet!
The hair and nails are actually organs!
The only places on our body without hair are the palms
of the hands, plantar surface of the feet, and the lips.
The digestion of the sweat produced by apocrine glands
by bacteria causes body odor.
The average amount of hairs on a person’s head is
120,000.
We lose 30,000 to 40,000 skin cells every minute.
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Created by Mark Lewis
CITATIONS
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Taylor, T. (n.d.). Integumentary System. In Inner Body.
Retrieved August 28, 2013, from
http://www.innerbody.com/anatomy/integumentary
Skin. (n.d.). In National Geographic. Retrieved August
28, 2013, from
http://science.nationalgeographic.com/science/healthand-human-body/human-body/skin-article.html
Brind'Amour, K. (2012, August 20). Get the Skinny on
Skin Disorders. In Health Line. Retrieved August 28,
2013, from http://www.healthline.com/health/skindisorders
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THE END
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