The Integumentary System
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Transcript of The Integumentary System
The Integumentary System
(Skin)
I. Introduction• The skin is like a coat for your body:
waterproof, stretchable, washable,
lasts a lifetime, and invisibly repairs
small cuts, rips, and burns
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II. Functions of SkinA. Protection
1. Mechanical damage - bumps, blows,
scrapes, cuts, etc.
2. Chemical damage - acidic or basic
substances
3. Thermal damage - heat or cold
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II. Functions of SkinA. Protection
4. UV radiation - produces melanin
5. Bacteria - barrier to germs
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II. Functions of SkinB. Body Temperature Regulation
1. Heat loss:
perspiration; dilation of
blood vessels near skin
2. Heat retention:
fat deposits; constriction of blood
vessels near skin
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II. Functions of Skin
C. Conservation of Body Water
*Keratin = waterproofing protein
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II. Functions of Skin
D. Excretion of Wastes
*Perspiration allows urea, uric acid,
sodium chloride, creatinine, lactic
acid, etc. to be released from the
body
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II. Functions of Skin
E. Receptors to Detect Outside Stimuli
*contains receptors that detect
temperature, pain, and pressure
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II. Functions of Skin
F. Vitamin Production
*contains sterols that convert to
Vitamin D when exposed to UV light
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III. Structure of the skin
III. Structure of the skin
A. Epidermis - outer skin layer composed
of stratified squamous epithelium
1. Sub-layers of the epidermis
III. Structure of the skin
a. Stratum corneum:
-top layer of the epidermis
-protective covering that contains
keratin
-barrier layer consisting of dead,
stratified squamous epithelium
III. Structure of the skin
b. Stratum lucidum:
-thin layer of clear cells
-contains eleidin (translucent
compound)
-found mainly in palms of hands and
soles of feet
III. Structure of the skin
c. Stratrum granulosum:
-consists of 3 - 5 layers of flattened
cells
-contains melanin
III. Structure of the skin
d. Stratum spinosum:
-consists of 8 - 10 layers of cells
-keratin is produced here
III. Structure of the skin
e. Stratum basale:
-deepest cell layer
-only cell layer in which cell division
occurs; receives nutrients from the
dermis
-most melanocytes found here
III. Structure of the skin
2. Why doesn’t a man bleed when he shaves, even though he is cutting off many cell layers?
- the epidermis is avascular
(no blood supply)
III. Structure of the skin
B. Dermis - dense connective tissue; “hide”, strong, stretchy layer that helps hold the body together
1. Sub-layers of the dermis
III. Structure of the skin
a. Papillary layer:
-outermost layer of dermis; attaches
epidermis to other skin layers
-has a blood supply
-contains fingerlike projections that
form ridges & bumps for traction
(fingerprints)
III. Structure of the skin
b. Reticular layer:
-deepest skin layer; makes up most of
the dermis and provides strength
“toughness”
-contains blood vessels, sweat & oil
glands, receptors, collagen & elastic
fibers
III. Structure of the skin
C. Hypodermis (subcutaneous tissue)
fatty layer that anchors skin to underlying organs; absorbs shock and insulates
IV. Skin Color
A. Three pigments contribute to skin color
1. Melanin - yellow to reddish brown
to black
2. Carotene
3. Hemoglobin
V. Appendages of the skin
A. Sebaceous (oil) glandsB. Sweat glands:
1. Eccrine - water; heat regulation 2. Apocrine - fats & proteins; puberty
C. HairD. Nails