1. SKIN
The Great Barrier

2. ORGAN SYSTEM

Integumentary System
Composed of multiple structures:
 Skin
 Hair
 Nails
 Sweat Glands
 Sebaceous Gland

3. SKIN STRUCTURE

Skin is composed of three main layers
Epidermis – the outermost layer of skin,
provides the body with water proofing and
a barrier for infection
 Dermis – deep portion of skin, contains
various glands, nerves and allows for
attachment of other anatomy
 Subcutaneous layer – innermost layer
containing fatty tissue


4. SKIN STRUCTURE

5. EPIDERMIS

Epi- prefix meaning upon, over

Dermat/o - combining form
meaning skin

6. EPIDERMIS

The epidermis is the thin outer membrane
layer of the skin

Composed of stratified squamous epithelium

Stratified squamous epithelium are a type of tissue
containing flat, scale-like cells that overlap into
layers

7. KERATIN



The deepest layer of the epidermis, known as
the basal layer, continually form new cells
As cells move to the outside layers, the cells
become filled with a hard protein, known as
keratin
Keratinization of these cells allow the skin to
act as an effective barrier to infection and
make the skin waterproof

8. MELANIN

The basal layer also
contains melanocytes,
which produce the black
pigment melanin

Melanin colors the skin
and protects against
damage from ultraviolet
rays of the sun

9. DERMIS

The dermis, also called
the corium, is the
middle layer of the skin

It is a much larger layer
than the epidermis, and
has a very good blood
supply

10. DERMIS

The dermis is composed of connective tissue
and collagen fibers

Collagen fibers are made from a strong,
fibrous protein present in connective tissue

These fibers form a flexible “glue” that gives
the tissues strength

11. DERMIS

The dermis contains many other accessory
pieces to the skin including







Hair follicles
Sweat glands
Sebaceous glands
Blood vessels
Lymph vessels
Sensory receptors
Nerve and muscle fibers

12. SUBCUTANEOUS LAYER

The deepest layer of the skin is the
subcutaneous, also called the hypodermis



Hypo – under, below
Cutane/o – skin
The subcutaneous layer is composed of fat
cells called lipocytes
These cells protect deeper tissues and act as
insulation for heat and cold

13. ACCESSORY ORGANS FOUND IN
SKIN

Hair – composed of
keratin



Hair shaft grows from
follicle towards surface
Arrector pili muscle
contracts to cause “goose
bumps”
Sebaceous gland –
found in dermis,
secretes sebum, which
lubricates hair and skin

14. ACCESSORY ORGANS FOUND IN
SKIN

Nails – flat plates of keratin that cover ends of
fingers and toes



Nail bodies cover the nail, connecting to the nail
bed
Nails grow longer from the nail root, found at the
base of the nail and covered by the soft tissue
known as the cuticle
Light, half moon area at the base of the nail is
called the lunula

15. ACCESSORY ORGANS FOUND IN
SKIN

16. ACCESSORY ORGANS FOUND IN
SKIN

Sweat glands – also known as sudoriferous
glands, are found throughout the body



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Around 2 million sweat glands in total
Located in the dermis, the sweat travels to the skin
surface through a sweat gland
The surface opening is called a sweat pore
Sweat, or perspiration cools the body as it
evaporates

17. SKIN


Skin is a great barrier providing protection from
infectious bacteria, protecting vital organs and
regulating your body temperature
Fun fact: the skin is the human body’s largest organ