The Integumentary System. Integumentary System Integumentary system = Skin Nails Hair Glands Nerve endings

The Integumentary System

Integumentary SystemIntegumentary system = Skin Nails Hair Glands Nerve endings

Integumentary System: FunctionsPROTECTION from:

Mechanical damage Chemical damage Bacterial damage antibacterial secretionsUV radiation melanin pigment protectsThermal damage cold/pain receptorsDessication keratin waterproofing

Even more functionsHelps with heat loss or heat retention sweat glands and capillaries

Helps excrete urea perspiration

Makes Vitamin D sunlight converts cholesterol molecules in our skin

Skin Structure

2 Types of Skin TissueEpidermisKeratinocytes that can make the protein keratin (become hard & tough)

DermisConnective tissue that contains glands, capillaries and nerves

EpidermisThe StratumsCorneumLucidumGranulosumSpinosumBasale

College Life Gives Snoopy Brains

Stratum BasaleThese are the stem cells of skin

As they mature, they climb the layers of epidermis

Melanocytes are here and make melanin (keratinocytes gobble up the melanin)

Melanin Pigment

Melanin Pigment Protects Nucleus

Stratum Spinosum

Stratum Granulosum

Stratum LucidumBy this point, cells are full of keratin and are dead

Stratum Corneum20 to 30 layers of dead skin cells filled with keratinWaterproofing materialThis layer is thicker on palms and solesBeauty is only skin deep?!

Harlequin IchthyosisAutosomal recessiveGenerate in 1 day the amount of skin a normal person would generate in 14 daysConstant care, moisturizing, bathing to remove keratin layerOldest living person is 24Blind from corneal abrasions

Harlequin Ichthyosis

Dermis: Papillary and Reticular

The Dermis Home of the Tattoo

Tattoo RemovalDermabrasionSalabrasion (rub with salt)CryosurgeryExcisionLatest: Q-switched lasersDifferent lasers for different color pigmentsBlack, purple, red easiestYellow, green hardest

Burns: 1st Degree1st degree: only epidermis is damagedHeal in 2 to 3 days without a problemSunburn without blistering

Burns: 2nd DegreeInjury to the epidermis and part of the dermisCharacterized by pain, redness, swelling, and blistersStill enough epithelial cells to regeneratePartial-thickness burn

Burns: 3rd DegreeWorstEntire epidermis and dermis is destroyedNo more stem cells, no blood supplyNo nerve endings (no pain, but only at first)Must skin graft

Examples of Burns

Rules of Nines

Skin Grafting

Albinism: Melanocytes, but no melanin

Albinism

Visual Problems in Albinism

Vitiligo: Destruction of Melanocytes

PsoriasisSilvery, scaly patches of skin overgrowthPrevalence 2 3 %Onset: 15-25 years of ageThought to be autoimmune

Cold SoresViral infectionHerpes Simplex Type 1

Hansens Disease (Leprosy)Spinalonga, Greece

3 Main Types of Skin CancerBasal cell carcinoma:most commonleast malignantsun-exposed areas99% cure rate with excision

3 Main Types of Skin CancerSquamous cell carcinoma:Shallow ulcer that wont healSun-exposed areasCan grow rapidlyMetastasizes (travels to lymph nodes and other parts of the body)

3 Main Types of Skin CancerMalignant melanoma:Only about 5% of all skin cancers, but incidence is on the riseArises from accumulated damage to DNA in a melanocyteChance for survival: 50%ABCD rule

ABCD Rule of Malignant MelanomasAsymmetry: 2 sides of the pigmented spot do not matchBorder irregularity: borders are not smooth but exhibit indentationsColor: pigmented spot contains areas of different colors (black, brown, tan, red)Diameter: spot is larger than 6 mm in diameter (size of pencil eraser)

Skin AppendagesSebaceous (Oil) Glands

Sweat Glands

Hair and Hair Follicles

Nails

Sebaceous GlandsEverywhere except palms and solesUsually empty into hair follicleMakes sebumKeeps skin soft/moistAntibacterialIncreased production during pubertyWhen gland is blocked: whiteheads/blackheads

Sweat Glands: 2 TypesEccrine glands: make sweatClear secretion of water, salts, urea, lactic acidAcidic, inhibits bacteriaApocrine glands: axilla (armpit) and genital areaContain sweat plus proteins/fats (not antibacterial)

Hair FolliclesHair follicle: makes the hairHair root: aliveHair shaft: dead material; almost all proteinArrector pili: tiniest muscles; goose bumps

NailsBody: thickened keratinRoot,nail fold and nail bed are aliveLunula: white moon

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