S3L1: structure and function

primary function for the epidermis

protect the body from th elements, wind, and uv

serves as barrier to viruses and bacteria

primary function for the dermis

contains blood vessels, lymph nodes, hair follicle, sweat glands, nerve endings

supply the epidermis with oxygen and nutrients

primary function for hypodermis

contains fat; insulate the body; provide protective padding around organs

vitamin D

keeps bones healthy and keeps immune system functioning

keratinocytes

contain the structural protien keratin

provides strength, flexability, and toughness

life cycle of keratinocytes

new cells are at the bottom of the epidermis and migrate to the top while increasing keratin production. when they reach the top they de and lose their necleus and organelles

melanocytes

produce melanin

shaped like nerve cells with long projections to deliver melanin (melanosomes) to keratinocytes

types of melanin

pheomelanin; reddish-yellow pigment appearing pink in color

eumelanin; brown and black varieties appearing brown in color

uvA & uvB

uv B is only 5% of all uv light that reaches earths surface while uvA is the other 95%

the integumentary system is useful for a lot of things like:

protection and touch

vitamin production

temperature regulation

to release heat, blood vessels…

dialate

to retain heat, blood vessels

constrict