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
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
16. ACCESSORY ORGANS FOUND IN
SKIN
Sweat glands – also known as sudoriferous
glands, are found throughout the body
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