Integumentary SystemProtecting you from the outside world

Parts of the systemSkin

◦Layers- dermis, epidermisHair folliclesNailsSweat GlandsSebaceous Glands

*Some consider other membranes as well (ex- mucosal). We will only look at skin

Skin2 layers

◦Epidermis◦Dermis

Epidermis◦Dead, keratinized skin, made of 5 layers of

dead skin ◦Constantly shed◦Holds melanocytes, make melanin, skin

pigmentDermis

◦Under epidermis◦Made of blood vessels, connective tissue

Within the skinHair folliclesSweat GlandsSebaceous Glands

Hair FolliclesCells within dermis divide by

mitosis◦As cells push up, keratinization

occurs (like epidermis)◦Type of keratin (genetically

determined) results in hair’s shape (straight, curly, etc.)

Goosebumps◦Small muscle pulls on hair, causing

to stand on end◦Evolutionary reaction to trap heat

Sweat GlandsSmall tubes beginning in dermal

layerTube exits on epidermis

◦Excretion contains Salt Urea Uric acid Ammonia Sugar

◦As water evaporates, removes heat from body

Sebaceous GlandsAlong sides of hair folliclesCreate oily substance that rubs

onto hair and skinIncrease production during

puberty, acne!

NailsAlso keratinizedAs keratin and air mix, white

substance is left on nail nearest skin

Nail bed grows nails1mm per week

DiseasesEczemaPoison Ivy/Poison

Oak/PoisonwoodAlbinismAthlete’s FootTreeman

EczemaAny inflammation of the

epidermisResult of infection, allergen, or

irritant

Causes redness, swelling, itching

Poison _________Plants that secrete chemicals

that irritate the skin of MOST people

Includes poison ivy, poison oak, poisonwood, and cashews!

Once oils washed off, rash cannot be spread◦You cannot spread by itching the

rash unless the oil is still on you

Poisonwood rashCashew

AlbinismRecessive genetic mutation

results in body’s inability to produce melanin, a pigment

Causes very pale skin, hair, eye coloration

Same mutation exists in many mammals

Albinism

Athlete’s FootFungal infection, primarily of feet,

but can occur anywhere on bodySpread by contact

◦This is why you wear shower shoes in college!!!

Athlete’s Foot

TreemanRare double-genetic disorder

resulting in body having difficulty regulating zinc levels

Causes large wart-like growths all over body

Treeman