Protection from water, air, infection, chemicals, UV radiation
Sensations such as pressure, heat, cold, and pain
Temperature regulation
Excretion of water through sweat
Production of vitamin D
Functions of the skin
top layer of the skin
composed of stratified squamous epithelial tissue
Epidermis
Layer of dead cells 20-30 thick. Thick, keratinized cells protect the deeper layers. Regularly shed from the body.
Stratum Corneum
a thin layer of translucent cells only found in thick skin of the
palms
and soles of feet
Stratum Lucidum
Cells here begin to flatten and disintegrate. Accumulate keratin granules, responsible for water-proofing the skin.
Stratum granulosum
“Spiny layer”. Named for the irregular shape of the cells. Several cells thick. Contains pre-keratin filaments.
Stratum spinosum
Constantly dividing and pushing up cells into the next layer.
Stratum Basale
spider-shaped epithelial cells found in the bottom 2 layers of the epidermis
Melanocytes
a pigment that is absorbed by nearby epidermal cells, melanocytes produce this pigment.
protects the skin against harmful UV rays.
Melanin
when UV radiation mutates a skin cell's DNA, the. cells begin to divide uncontrollably
Skin cancer
Uncontrolled division of melanocytes
Melanoma
uncontrolled division of cells in the stratum basale layer
Basal cell carcinoma
uncontrolled division of cells in the stratum spinosum layer
Squamous cell carcinoma
composed of dense irregular connective tissue
contains nerves, blood vessels, sweat glands, and hair follicles
dermis
boundary between the epidermis and. the dermis is a wavy layer
dermal papillae
dermal papillae is the cause of your ____
fingerprints or epidermal ridges
made of loose connective tissue
papillary layer
made of bundles of collagen fibers
reticular layer
the arrangement of the collagen fibers cause ____
lines of cleavage/tension
how can blood flow change in the dermis change?
During exercise, the blood vessels in the dermis swell causing skin to appear red.
This allows heat from the blood to dissipate, cooling the body.
When blood supply to the skin is restricted for a prolonged time, decubitus ulcers (bedsores) can form.
known as the subcutaneous layer
compose of loose, fatty connective tissue that connects the skin to muscle or bone
insulates and stores nutrients
hypodermis
sweat glands
sudoriferous gland
oil gland
produce sebum
holocrine glands
lubricates skin and hair, kills bacteria
Sebaceous gland
Merocrine sweat glands that are abundant and often found on the palms, soles of feet, and forehead
sweat glands are long tubes that open into pores on the surface of the skin.
Eccrine
found almost exclusively in the armpit and genital areas
bacteria begin to break down fat & proteins causing body odor.
Apocrine
What is the function of hair?
head hair keeps in heat and protects us from the sun
body hair alerts us to insects
eyelashes protect the eyes
nose hair prevents the entry of foreign objects
part of the hair that sticks out of the skin
hair shaft
The hair shaft is protected by the outmost layer called ____
cuticle
hair cells divide within the follicle in a region called ____
hair bulb
attach to the hair shaft to make hair "stand on end"
arrector pili
produces heavily keratinized cells
nail matrix
the nail is protected on ____ ____ by nail _____
three sides; folds
whiter due to thickness of nail
Lunula
provides a protective seal for the nail matrix.
eponychium