SKINSKIN

The Great BarrierThe Great Barrier

ORGAN SYSTEMORGAN SYSTEM

Integumentary SystemIntegumentary SystemComposed of multiple structures:Composed of multiple structures:

SkinSkin HairHair NailsNails Sweat GlandsSweat Glands Sebaceous GlandSebaceous Gland

SKIN STRUCTURESKIN STRUCTURE

Skin is composed of three main layersSkin is composed of three main layers Epidermis – the outermost layer of skin, Epidermis – the outermost layer of skin,

provides the body with water proofing and provides the body with water proofing and a barrier for infectiona barrier for infection

Dermis – deep portion of skin, contains Dermis – deep portion of skin, contains various glands, nerves and allows for various glands, nerves and allows for attachment of other anatomyattachment of other anatomy

Subcutaneous layer – innermost layer Subcutaneous layer – innermost layer containing fatty tissuecontaining fatty tissue

SKIN STRUCTURESKIN STRUCTURE

EPIDERMISEPIDERMIS

Epi- prefix meaning upon, overEpi- prefix meaning upon, over

Dermat/o - combining form Dermat/o - combining form meaning skinmeaning skin

EPIDERMISEPIDERMIS

The epidermis is the thin outer membrane The epidermis is the thin outer membrane layer of the skinlayer of the skin

Composed of Composed of stratified squamous epitheliumstratified squamous epithelium Stratified squamous epithelium are a type of tissue Stratified squamous epithelium are a type of tissue

containing flat, scale-like cells that overlap into containing flat, scale-like cells that overlap into layerslayers

KERATINKERATIN

The deepest layer of the epidermis, known as The deepest layer of the epidermis, known as the the basal layerbasal layer, continually form new cells, continually form new cells

As cells move to the outside layers, the cells As cells move to the outside layers, the cells become filled with a hard protein, known as become filled with a hard protein, known as keratinkeratin

Keratinization of these cells allow the skin to Keratinization of these cells allow the skin to act as an effective barrier to infection and act as an effective barrier to infection and make the skin waterproofmake the skin waterproof

MELANINMELANIN

The basal layer also The basal layer also contains melanocytes, contains melanocytes, which produce the black which produce the black pigment melaninpigment melanin

Melanin colors the skin Melanin colors the skin and protects against and protects against damage from ultraviolet damage from ultraviolet rays of the sunrays of the sun

DERMISDERMIS

The dermis, also called The dermis, also called the the coriumcorium, is the , is the middle layer of the skinmiddle layer of the skin

It is a much larger layer It is a much larger layer than the epidermis, and than the epidermis, and has a very good blood has a very good blood supplysupply

DERMISDERMIS

The dermis is composed of connective tissue The dermis is composed of connective tissue and and collagen fiberscollagen fibers

Collagen fibers are made from a strong, Collagen fibers are made from a strong, fibrous protein present in connective tissuefibrous protein present in connective tissue

These fibers form a flexible “glue” that gives These fibers form a flexible “glue” that gives the tissues strengththe tissues strength

DERMISDERMIS

The dermis contains many other accessory The dermis contains many other accessory pieces to the skin includingpieces to the skin including Hair folliclesHair follicles Sweat glandsSweat glands Sebaceous glandsSebaceous glands Blood vesselsBlood vessels Lymph vesselsLymph vessels Sensory receptorsSensory receptors Nerve and muscle fibersNerve and muscle fibers

SUBCUTANEOUS LAYERSUBCUTANEOUS LAYER

The deepest layer of the skin is the The deepest layer of the skin is the subcutaneous, also called thesubcutaneous, also called the hypodermis hypodermis Hypo – under, below Cutane/o – skinHypo – under, below Cutane/o – skin

The subcutaneous layer is composed of fat The subcutaneous layer is composed of fat cells called cells called lipocyteslipocytes

These cells protect deeper tissues and act as These cells protect deeper tissues and act as insulation for heat and coldinsulation for heat and cold

ACCESSORY ORGANS FOUND IN ACCESSORY ORGANS FOUND IN SKINSKIN

HairHair – composed of – composed of keratinkeratin Hair shaft grows from Hair shaft grows from

folliclefollicle towards surface towards surface Arrector pili Arrector pili muscle muscle

contracts to cause “goose contracts to cause “goose bumps”bumps”

Sebaceous glandSebaceous gland – – found in dermis, found in dermis, secretes secretes sebumsebum, which , which lubricates hair and skinlubricates hair and skin

ACCESSORY ORGANS FOUND IN ACCESSORY ORGANS FOUND IN SKINSKIN

NailsNails – flat plates of keratin that cover ends of – flat plates of keratin that cover ends of fingers and toesfingers and toes Nail bodies Nail bodies cover the nail, connecting to the cover the nail, connecting to the nail nail

bedbed Nails grow longer from the Nails grow longer from the nail rootnail root, found at the , found at the

base of the nail and covered by the soft tissue base of the nail and covered by the soft tissue known as the known as the cuticlecuticle

Light, half moon area at the base of the nail is Light, half moon area at the base of the nail is called the called the lunulalunula

ACCESSORY ORGANS FOUND IN ACCESSORY ORGANS FOUND IN SKINSKIN

ACCESSORY ORGANS FOUND IN ACCESSORY ORGANS FOUND IN SKINSKIN

Sweat glands – Sweat glands – also known as also known as sudoriferous sudoriferous glandsglands, are found throughout the body, are found throughout the body Around 2 million sweat glands in totalAround 2 million sweat glands in total Located in the dermis, the sweat travels to the skin Located in the dermis, the sweat travels to the skin

surface through a surface through a sweat glandsweat gland The surface opening is called a The surface opening is called a sweat poresweat pore

Sweat, or Sweat, or perspirationperspiration cools the body as it cools the body as it evaporatesevaporates

SKINSKIN

Skin is a great barrier providing protection from Skin is a great barrier providing protection from infectious bacteria, protecting vital organs and infectious bacteria, protecting vital organs and regulating your body temperatureregulating your body temperature

Fun fact: the skin is the human body’s Fun fact: the skin is the human body’s largest organlargest organ