TheThe INTEGUMENTARY INTEGUMENTARY

System System

Functions of the SkinFunctions of the Skin• ProtectionProtection• Regulation of Body TemperatureRegulation of Body Temperature• Reception of StimuliReception of Stimuli• ExcretionExcretion• Synthesis of Vitamin DSynthesis of Vitamin D• Immunological FunctionImmunological Function

EpidermisEpidermis

• Outer layer of skinOuter layer of skin• Avascular - no Avascular - no

blood vesselsblood vessels• Composed of Composed of

stratified squamous stratified squamous epitheliumepithelium

DermisDermis

• Layer of skin under Layer of skin under the epidermisthe epidermis

• Made up of collagen Made up of collagen and elastic and elastic connective tissue connective tissue fibers fibers

• Contains the blood Contains the blood vessels, hair vessels, hair follicles, and nerve follicles, and nerve endings of the skinendings of the skin

NailsNails• Plates of Plates of tightly packed, hard, tightly packed, hard,

keratinized cells of the epidermiskeratinized cells of the epidermis• Forms a Forms a clear solid covering clear solid covering over the over the

dorsal surface of the ends of the digitsdorsal surface of the ends of the digits• Provides protection to ends of digitsProvides protection to ends of digits• Helps to grasp and manipulate small Helps to grasp and manipulate small

objectsobjects

Portions of NailsPortions of Nails• Nail Body - portion of nail Nail Body - portion of nail

visiblevisible– Free Edge - extends Free Edge - extends

beyond the digitsbeyond the digits– Root - hidden in proximal Root - hidden in proximal

nail groovenail groove– Lunula - whitish semilunar Lunula - whitish semilunar

area at proximal end of area at proximal end of the nail bodythe nail body

• Eponychium - CuticleEponychium - Cuticle• Nail Matrix - epithelium at Nail Matrix - epithelium at

proximal end of the nailproximal end of the nail– mitosis and nail growth mitosis and nail growth

from this areafrom this area– grows at a rate of about 1 grows at a rate of about 1

mm per weekmm per week

Hair (Pili)Hair (Pili)• Primary function is Primary function is protectionprotection

– guards the scalp from injury and guards the scalp from injury and sunlightsunlight

– eyebrows - eyelashes protect the eyeeyebrows - eyelashes protect the eye– ears and nostrils keep out foreign ears and nostrils keep out foreign

objectsobjects• Helps regulate body temperatureHelps regulate body temperature• Touch receptors Touch receptors associated with associated with

hair follicleshair follicles

Components of HairComponents of Hair• Shaft - portion of hair Shaft - portion of hair

above the surface of the above the surface of the skinskin

• Root - portion of hair Root - portion of hair below the skinbelow the skin– Hair Follicle - cells that Hair Follicle - cells that

surround the rootsurround the root• Bulb - onion shaped Bulb - onion shaped

structure at the base of structure at the base of each hair follicleeach hair follicle– Matrix - area of cell Matrix - area of cell

division and hair growthdivision and hair growth

Arrector Pili MuscleArrector Pili Muscle• Bundle of Bundle of smooth smooth

muscles associated muscles associated with each hair that with each hair that makes the hair stand makes the hair stand up when contractedup when contracted– coldcold– frightenedfrightened– aggressive posturingaggressive posturing– emotionsemotions

Receptors of the Skin – Receptors of the Skin – Nerve EndingsNerve Endings

• Consists of Consists of distal ends of distal ends of neuronsneurons

• Similar to Similar to antennae in antennae in that they that they receive receive information information about the about the environmentenvironment

Sebaceous GlandsSebaceous Glands• Oil glands Oil glands usually usually

associated with hair associated with hair folliclesfollicles

• Secrete an oily Secrete an oily substance called sebum substance called sebum a mixture of fats, a mixture of fats, cholesterol, protein and cholesterol, protein and inorganic saltsinorganic salts

• Keeps hair from drying Keeps hair from drying out out and becoming and becoming brittlebrittle

• Keeps skin soft and Keeps skin soft and pliablepliable

• Inhibits growth of Inhibits growth of certain bacteriacertain bacteria

Sudoriferous GlandsSudoriferous Glands(Sweat Glands)(Sweat Glands)

• Glands Glands secrete secrete sweat sweat --

• Primary function - Primary function - regulates body regulates body temperature by temperature by evaporation of waterevaporation of water

• Eliminates some Eliminates some waste productswaste products

• Two types of sweat Two types of sweat glands:glands:– Apocrine GlandsApocrine Glands– Eccrine GlandsEccrine Glands

Ceruminous GlandsCeruminous Glands• EarwaxEarwax• Traps foreign particlesTraps foreign particles

Hypodermis Hypodermis (Subcutaneous) Layer(Subcutaneous) Layer

• Not part of the true Not part of the true skinskin

• Connective tissue that Connective tissue that connects the skin to connects the skin to the muscle and organs the muscle and organs underneathunderneath

• Also called the Also called the superficial fasciasuperficial fascia

• Contains Contains nerve nerve endings responsible endings responsible for deep pressure for deep pressure

• May May contain enlarged contain enlarged fat cellsfat cells in obese in obese individualsindividuals

DISORDERS, DISEASES, DISORDERS, DISEASES, AND HOMEOSTATIC AND HOMEOSTATIC

IMBALANCES OF THE IMBALANCES OF THE INTEGUMENTARY INTEGUMENTARY

SYSTEMSYSTEM

Skin CancersSkin Cancers• cancerous growths of skin tissuecancerous growths of skin tissue• often caused by prolonged often caused by prolonged

exposure to the sunexposure to the sun• three main types of skin cancersthree main types of skin cancers

– Basal Cell CarcinomasBasal Cell Carcinomas– Squamous Cell CarcinomasSquamous Cell Carcinomas– Malignant MelanomasMalignant Melanomas

Basal Cell CarcinomasBasal Cell Carcinomas• Tumors that arise from the Tumors that arise from the

basal cells of the epidermisbasal cells of the epidermis• Slow growing - rarely Slow growing - rarely

metastasizemetastasize• Account for over 75% of all Account for over 75% of all

skin cancersskin cancers• Caused by chronic over-Caused by chronic over-

exposure to the sunexposure to the sun• More common in fair More common in fair

skinned individuals over 40 skinned individuals over 40 years of age years of age

• Treated by excision of the Treated by excision of the tumortumor

Squamous Cell Squamous Cell CarcinomasCarcinomas• Tumors that arise from Tumors that arise from

the squamous cells of the squamous cells of the epidermisthe epidermis

• Vary in the ability to Vary in the ability to metastasizemetastasize

• Arise from pre-existing Arise from pre-existing lesions on sun exposed lesions on sun exposed skinskin

• More common in older, More common in older, fair skinned malesfair skinned males

• Treated by excision or Treated by excision or X-Ray irradiationX-Ray irradiation

Malignant MelanomasMalignant Melanomas• Cancerous growths that arise Cancerous growths that arise

from melanocytes of the stratum from melanocytes of the stratum basalebasale

• Leading cause of skin cancer Leading cause of skin cancer deathsdeaths

• Spreads through the lymph and Spreads through the lymph and bloodblood

• Least common type of skin Least common type of skin cancer (3%)cancer (3%)

• Caused by chronic over-Caused by chronic over-exposure to UV lightexposure to UV light

• Treated by surgical removal of Treated by surgical removal of large amounts of tissue and X-large amounts of tissue and X-Ray irradiationRay irradiation

ABCD Method to Assess ABCD Method to Assess Skin CancerSkin Cancer

• A - AsymmetryA - Asymmetry• B - BorderB - Border• C - ColorC - Color• D - Diameter D - Diameter

Skin Cancer Risk Skin Cancer Risk FactorsFactors• Skin TypeSkin Type

– light skin - greater risklight skin - greater risk• Geographic LocationGeographic Location

– higher altitude - greater riskhigher altitude - greater risk• AgeAge

– older - greater riskolder - greater risk• Immunological StatusImmunological Status

– immuno-suppresed - greater riskimmuno-suppresed - greater risk• Personal HabitsPersonal Habits

– occupations, leisure activities, recreation occupations, leisure activities, recreation

Decubitus UlcersDecubitus Ulcers• bed sores - pressure bed sores - pressure

soressores• lesion caused by lesion caused by

prolonged pressure prolonged pressure resulting in blood resulting in blood deficiency to a tissue deficiency to a tissue overlying a bony overlying a bony projectionprojection

• seen most frequently in seen most frequently in individuals bedridden individuals bedridden for prolonged periods of for prolonged periods of timetime