Integumentary System_PowerPoint
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Integumentary System
Turn to your neighbor…what is
the integumentary system?
Skin
Glands
Hair
Nails
FUNCTION: Act as a protective barrier to
the outside world.
Body Bucket
retains body fluids
protects against disease
eliminates waste products
regulates body temperature
Basically, holds all your “stuff” from falling
out or getting contaminated.
How skin protects…
Serving as a barrier against infection and
injury
Helping to regulate body temperature
Removing waste products from the body
Providing protection against ultraviolet
radiation from the sun
Producing vitamin D
Three main layers
Epidermis
Dermis
Hypodermis
Sensory receptors
Perceives sensations such as:
Pressure
Heat
Cold
Pain
All of which are then transmitted to the
nervous system.
EPIDERMIS
Outer most layer of skin
Composed of many sheets of flattened, scaly
epithelial cells
Thin layer of skin made mostly of dead cells
Undergoes rapid cell division
New cells are produced pushing older cells
to the surface of the skin
The older skin begins making keratin
There are no blood vessels in the epidermis
which is why a small scratch will not cause
bleeding
Keratin
Is a tough fibrous protein
Forms basic structure for hair, nails and
calluses
Eventually, the keratin-producing cells die
and form a tough, flexible waterproof
covering on the surface of the skin
Melanin (a dark brown pigment)
Skin pigment
Both light skinned and dark skinned
people have roughly the same number of
melanocytes (cells that produce pigment)
The difference in our skin color is caused
by the amount of melanin the melanocytes
produce and distribute.
Amount of Melanin
Dependent on two factors
Heredity
Length of time skin is exposed to
ultraviolet radiation
Role – absorption of ultraviolet
radiation
DERMIS
Middle thick layer of the skin
composed of living cells
Contains: blood vessels, nerve
endings, glands, sense organs,
smooth muscles, and hair follicles
Helps control body temperature
Body temperature
On cold days, the blood vessels
(arteries) narrow/constrict
• Decreases surface area in order to
conserve body heat
On hot days the blood vessels
(arteries) widen/expand
• warming the skin and increasing heat
loss
Goose Bumps
Tiny muscle fibers attach to hair
follicles contract and pull hair
upright when you are cold or afraid
producing what we call “goose
bumps”
Dermis contains two major glands
Sweat glands
Secretions are stimulated by nerve impulses that
cause the production of sweat when the
temperature of the body is raised
They help cool the body off
Oil glands
Produce oily secretion known as sebum that
spreads out along the surface of the skin and
keeps the keratin rich epidermis flexible and
waterproof
Hypodermis
This layer is beneath the dermis
A layer of fat and loose connective tissue
that insulates the body and acts as an
energy reserve.
What causes blisters and calluses?
the rubbing of the separate skin
layers
the epidermis and the dermis
separate
tissue fluid may collect between the
layers
skin prone to this pressure will create
an area of thicker epidermis causing
a callus
Burns
Severity ranges from minor to fatal
First degree burns
Only the superficial epidermis is affected
Painful but no blistering
Causes death of epidermal cells
Second degree burns
Deeper layers of the epidermis are charred
Inflammations, blisters and painful
…burns continued
Third degree burns
The entire epidermis is charred or burned away,
and the burn may extend into the dermis
Not usually painful at first if the receptors in the
dermis have been destroyed
Extensive third degree burns
Loss of skin
Potentially life threatening because the natural
barrier has been destroyed exposing tissue that
is extremely susceptible to infection and
dehydration
Hair
Produced by cells at the base of the
structures called hair follicles
Hair follicles – tube like pockets of
epidermal cells that extend into the dermis
Individual hairs are actually large columns
of dead cells that have been filled with
keratin
Hair gets color from melanin
Protects and insulates the body
Nails
Grow from rapidly divided cells known as the nail
matrix or nail root
Nail matrix is located near the tips of the fingers and
toes
During cell division, the cells fill with keratin and
produce a tough, strong platelike nail that covers
and protects the tips of the fingers and toes
The pinkish color comes from the blood vessels in
the nail bed
Nails grow at a rate of 0.5 to 1.2 mm per day
Finger nails grow faster than toe nails
Diagram of the skin
Fun Facts
Human body’s largest organ
Integumentary derived from a Latin word
meaning “to cover”
The outer layer of dead skin cells is shed
or washed away once every 14 to 28 days