The
Integumentary
System
Skin, Hair and Nails
Now using the microscopes. Examine
your skin, hair and nails.
In your spiral, diagram what you see.
Organs of the
integumentary system
The name is derived from the
Latin integumentum, which
means “a covering.”
skin
hair
nails
Label and color the parts of the
integumentary system
finger nail
Skin
The largest organ in your body
Functions
Covers the body and prevents water loss
Protects the body from injury and infection
Regulates body temperature
Eliminates wastes (sweat)
Produces vitamin D
Gathers information about the environment
Stores fat for fuel and insulation
Prevents Water Loss
Skin prevents water from leaking out of
your body
Prevents Infection
Skins acts as a barrier to bacteria and
viruses
Maintains Homeostasis
Helps to keep the body temperature
normal
Has blood vessels that tell the body
when it is hot or cold
Hot – blood vessels get larger and sweating
occurs
Cold – blood vessels constrict to keep blood
in the body’s core
Eliminates Waste
Sweating eliminates dissolved waste
from your body
Gathers Information
Skin contains nerves that can feel pain
or pressure
Provide Vitamin D
With the help of sunlight, your skin
produces vitamin D
Vitamin D is essential in calcium
absorption from food
Layers of Skin
Skin consists of three main layers
epidermis
dermis
subcutaneous
layer
subcutaneous
layer
Epidermis
 Outermost layer
 30-60 cells thick
 No nerves or blood vessels
 Top layer is dead
 New cells formed at the bottom of this layer
 Skin cells shed every 2 weeks
 Where nails grow
 Contains melanin
Epidermis
 Where nails grow
 Contains melanin
 Every minute, 30,000 - 40,000 skin cells fall off
 95% of your skin cells make new cells
 5% make melanin
 More sun exposure
= more melanin (tan)
Dermis
 Middle layer
 Contains nerves and
blood vessels
 Contains sweat
glands, oil glands
and hair follicles
 Contains collagen
and elastin that
allows skin to
stretch
subcutaneous layer
 Made mostly of fat
 Keeps you warm
 Absorbs shock
 Attaches your skin
to the underlying
tissue
hair
Made of a strong, dead protein, called
keratin
Grows out of a tiny tube called a follicle
Hair growth is caused by rapid mitosis
in the follicle
Hair follicles are everywhere except
lips
palms
soles
hair
Over 100,000 follicles on the scalp
Each follicle is attached to a gland that
secretes sebum (oil)
Color is partially determined by
melanin
nails
Modified hair that grows from your
cuticle
Made of keratin
No nerve endings
Protects the end of fingers and toes
Takes 6 months to grow from cuticle to
tip
nails
Fingernails grow faster than toenails
Nails grow faster on your dominant
hand
Nails DO NOT grow after death
Body systems that work with the
integumentary system;
respiratory system to get oxygen
and remove carbon dioxide
circulatory system to deliver
oxygen
excretory system to eliminate
waste