Download Integumentary System - School District of La Crosse

Fast Skin Facts
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The average adult has 21 square feet of skin (2 sq m) which
weighs 7lb (3.2 kg) and has approximately 300 million skin cells.
On average each square half inch of skin contains:
10 hairs, 15 sebaceous glands, 100 sweat glands, 3.2 feet (1m) of
tiny blood vessels
Skin is thickest on the palms & soles (1.2mm to 4.7mm) and
thinnest on the lips and around the eyes.
Every skin cell on your body is shed and replaced about every
52-75 days but can be much quicker in some skin diseases such
as psoriasis.
An average of 40 kilos of skin is shed during a lifetime
Integumentary System
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Consists of
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skin
hair
glands
nails
Largest organ of the human
body the
Skin accounts for 16% of the
bodies mass!
Functions
1.
Protection
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Disease (micro-invaders)
Loss of fluids
Physical injury
UV Light
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3.
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Communication
Receptors
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2.
Regulation of Temp
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Sweat
Insulation
Blood supply
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Hot/cold
Pain
Touch
Functions
4.
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Vitamin D Production
Calcium absorption
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5.
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For bones
For muscle contraction
Excretion of Wastes
sweat
Skin Cross Section
Epidermis
Dermis
Dermis
Subcutaneous
(Hypodermis)
Epidermis
Dead
Living
The epidermis is divided
into two layers, dead and
living cells.
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Living cells of the epidermis replicate, pushing their
way towards the surface.
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The cells flatten and the organelles
disintegrate.
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Eventually the living cells of the
inner epidermis become the dead,
tough, waterproof, and flexible
outer layer.
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As the living cells replicate they produce two
proteins
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Keratin: tough protective protein
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Melanin: pigment
Localized loss of
melanocytes (the cells
that produce melanin)
Differences in melanocyte density
leads to variation in skin color
Epidermis
Dermis
•blood vessels
• nerve endings
•glands
•sense organs
•smooth muscles
• hair follicles.
Skin Cross Section
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Two major types
1.
Sweat glands
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Eccrine- thin and watery
Apocrine- thick, kicks in at
puberty
2.
Sebaceous glands
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Sebum- an oil that coats
the surface of the skin
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flexibility and
waterproofing
Hair Follicle
Subcutaneous tissue
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Layer of fat
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Insulation
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Food reserve
• Nails grow rapidly from the nail root.
• During cell division the nail root fills with keratin
producing a plate-like nail.
• Fingernails grow 4 times
faster than toe nails with
an average rate of 3 millimeters
per month.
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Functions of Integumentary system.
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The layers of the skin.
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Various components of the epidermis
and dermis, including the nails.