anatomy

melan-

dark

seb-

oil

sudor-

sweat

derm-

skin

epi-

upon

hypo-

below

kerat-

hard

pil

hair

ungu

nail

Protection

from water

Sensations

such as pressure

Temperature regulation

body can be heated or cooled by sweat and blood flow near surface

Excretion

of waste through sweat

Production

of Vitamin D

Epidermis

the top layer of skin; composed of stratified squamous epithelial tissue

Stratum corneum layer

dead cells

Stratum lucidum

a clear layer

Stratum granulosum

cells begin to flatten and disintegrate

Stratum spinosum

"spiny layer"

Stratum basale

single layer of columnar cells

Melanocytes

spider-shaped epithelial cells that produce a pigment called melanin

Difference between dark-skinned and light-skinned people

different amount of melanin produced

Melanin function

protects skin from UV rays

UV radiation effect

mutates a skin cell's DNA

Dermis composition

dense irregular connective tissue

Boundary between epidermis and dermis

a wavy layer called the dermal papillae; this irregular surface is the cause of your fingerprints (or epidermal ridges)

Fingerprints/ridges function

increase friction allowing us to pick up objects more easily

Papillary layer

made of loose connective tissue

Reticular layer

made of bundles of collagen fibers

Lines of cleavage (tension)

the arrangement of collagen fibers in the dermis

Lines of cleavage importance for surgeons

quick healing and scar tissue; cuts should be made parallel to the lines of cleavage

Blood flow in the dermis during exercise

blood vessels in the dermis swell

Decubitus ulcers (bedsores)

can form when blood supply to the skin is restricted for a prolonged time

Hypodermis (subcutaneous layer)

not actually a part of the skin; composed of loose fatty connective tissue that connects the skin to muscle or bone; also insulates and stores nutrients

Hair and nails composition

made of hard keratin

Function of head hair

keeps heat in and protects from sun

Function of body hair

alerts to insects

Function of eyelashes

protect eyes

Function of nose hair

prevents entry of foreign objects

Shaft

the part of the hair that sticks out of the skin

Hair follicle (root)

located within the dermis

Hair bulb

region where hair cells divide within the follicle

Hair cell contents

filled with keratin and pigment

Arrector pili muscles

attach to the hair shaft to make hair "stand on end"

Nail function

protective and useful as tools

Free edge of nail

visible

Body of nail

visible

Root of nail

not visible

Nail bed

supports the nail

Nail matrix

produces heavily keratinized cells which become the nail body

Nail protection

protected on three sides by nail folds

Lunula ("little moon")

whiter due to the thickness of the nail

Eponychium (cuticle) function

protective seal for the nail matrix

Hair and nails composition

made of hard keratin

Function of head hair

keeps heat in and protects from sun

Function of body hair

alerts to insects

Function of eyelashes

protect eyes

Function of nose hair

prevents entry of foreign objects

Shaft

the part of the hair that sticks out of the skin

Hair follicle (root)

located within the dermis

Hair bulb

region where hair cells divide within the follicle

Hair cell contents

filled with keratin and pigment

Arrector pili muscles

attach to the hair shaft to make hair "stand on end"

Nail function

protective and useful as tools

Free edge of nail

visible

Body of nail

visible

Root of nail

not visible

Nail bed

supports the nail

Nail matrix

produces heavily keratinized cells which become the nail body

Nail protection

protected on three sides by nail folds

Lunula ("little moon")

whiter due to the thickness of the nail

Eponychium (cuticle) function

protective seal for the nail matrix

Burned tissue causes

heat

Limiting fluid loss

main concern of burns; loss of fluid can cause the heart and kidneys to shut down resulting in shock

Rule of Nines

used by medical professionals to determine the extent of tissue damage so they know how much fluid is required

Preventing infection

second main concern; burns need to be wrapped & treated to prevent infection

Burns near head

face

1st Degree burn

only the epidermis is damaged; skin is red & uncomfortable

2nd Degree burn

the epidermis & part of the dermis are damaged; skin is red

3rd Degree burn

epidermis and dermis are destroyed

4th Degree burn

tissue damage reaches muscle & bone; skin graft required

Skin grafts

required for 3rd and 4th degree burns to recover the damaged area because there is no more epithelial tissue for regeneration