The integumentary system consists of the skin, hair nails and
exocrine glands. Has three layers: the epidermis, dermis, and
subcutaneous layer Created by Mark Lewis 2
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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. MODEL OF THE SKIN Created by Mark Lewis
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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. Created by Mark Lewis 5
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1) Stratum basale- deepest layer, contains the stem cells that
make all the other epidermal cells 2) Stratum spinosum- contains
the langerhans cells and rows of prickly keratinocytes 3) Stratum
granulosum- location where keratinocytes produce waxy lamellar
granules to waterproof the skin 4) Stratum lucidum- made of dead
keratinocytes 5) Stratum corneum- outermost layer, made of rows of
dead keratinocytes, this layers purpose is protection. Created by
Mark Lewis 6
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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. Created by Mark Lewis 8
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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
Created by Mark Lewis 9
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10 (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. Created by Mark Lewis 11
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Created by Mark Lewis 12
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The skin regulates the bodys 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: 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 Created by Mark Lewis 13
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Created by Mark Lewis 14
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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
The kidneys later convert Vitamin D3 into Vitamin D that can be
used by the body. Created by Mark Lewis 15
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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 Created
by Mark Lewis 16
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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. Created by Mark Lewis
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Skin, Skin Information, Facts, News, Photos -- National
Geographic Skin, Skin Information, Facts, News, Photos -- National
Geographic http://science.nationalgeographic.com/scienc
e/health-and-human-body/human-body/skin- article.html Created by
Mark Lewis 18
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Created by Mark Lewis 19 HAIR NAILSSWEAT GLANDS SEBACEO- US
GLANDS
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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. 1) Follicle- a depression of
epidermal cells into the dermis; place where keratinocytes are made
2) Hair root- located within the follicle and below the skins
surface 3) Hair shaft- part outside of the skin and has three
layers (see next slide) Created by Mark Lewis 20
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1) Cuticle- outermost layer made of keratinocytes, which are
stacked like shingles 2) Cortex- the spindle-shaped cells in the
cortex contain the pigments that give hair its color and width 3)
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 Created by Mark Lewis 21
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Created by Mark Lewis 22
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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. Created by Mark
Lewis 23
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1) Nail root- portion found under the skin 2) Nail body-
visible portion of the nail 3) Free edge- the end part of the nail
that has grown beyond the end of the digit Created by Mark Lewis
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Sweat glands are exocrine glands that are found in the dermis.
There are two types of sweat glands: 1. Eccrine sweat glands- found
in most regions of the skin; produce a water and sodium chloride
secretion; these glands are used to lower the bodys temperature 2.
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) Created by Mark Lewis
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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 It also waterproofs and makes
the skin elastic It lubricates and shields the hair cuticles
Created by Mark Lewis 26
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Special exocrine glands in the dermis of the ear canals They
produce a waxy substance called cerumen. Cerumen protects ear
canals and moistens the eardrum It also reaps foreign substance in
the ear canal Its made constantly and is pushed to the outside of
the ear canal. Created by Mark Lewis 27
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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 Created by Mark Lewis 28
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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 Created by
Mark Lewis 29
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Did you know that an average persons 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 persons head is
120,000. We lose 30,000 to 40,000 skin cells every minute. Created
by Mark Lewis 30
Slide 32
Taylor, T. (n.d.). Integumentary System. In Inner Body.
Retrieved August 28, 2013, from
http://www.innerbody.com/anatomy/integumentary
http://www.innerbody.com/anatomy/integumentary Skin. (n.d.). In
National Geographic. Retrieved August 28, 2013, from
http://science.nationalgeographic.com/science/health-
and-human-body/human-body/skin-article.html
http://science.nationalgeographic.com/science/health-
and-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/skin-
disordershttp://www.healthline.com/health/skin- disorders Created
by Mark Lewis 31