ANATOMYANATOMY

INTEGUMENTARY INTEGUMENTARY SYSTEMSYSTEM

Chapter 4Chapter 4

Classifications of Classifications of MembranesMembranes

EpithelialEpithelial CutaneousCutaneous MucosaMucosa SerousSerous

ConnectiveConnective SynovialSynovial

Cutaneous MembranesCutaneous Membranes Cutaneous- a dry membraneCutaneous- a dry membrane

Outermost protective boundary (skin)Outermost protective boundary (skin)

Superficial epidermisSuperficial epidermis Keratinized Keratinized stratified stratified

squamous epitheliumsquamous epithelium

Underlying dermisUnderlying dermis Mostly dense Mostly dense

connective tissueconnective tissue

MucosaMucosa Surface epitheliumSurface epithelium

Type depends on siteType depends on site

Underlying loose connective Underlying loose connective tissue (lamina propria)tissue (lamina propria)

Lines all body cavities Lines all body cavities that open to the that open to the exterior body surfaceexterior body surface

Often adapted Often adapted for for absorption absorption or secretionor secretion

SerousSerous Surface simple squamous Surface simple squamous

epitheliumepithelium Underlying areolar Underlying areolar

connective tissueconnective tissue Lines open body cavities Lines open body cavities

that are closed to the that are closed to the exterior of the bodyexterior of the body

Serous layers separated by Serous layers separated by serous fluidserous fluid

Specific Serous Specific Serous MembranesMembranes PeritoneumPeritoneum

Abdominal Abdominal cavitycavity

PleuraPleura Around the Around the

lungslungs

PericardiumPericardium Around the Around the

heartheart

Connective- SynovialConnective- Synovial

Synovial Synovial membranemembrane Connective tissue Connective tissue

onlyonly Lines fibrous Lines fibrous

capsules capsules surrounding jointssurrounding joints

Skin’s FunctionsSkin’s Functions Protects deeper tissues from:Protects deeper tissues from:

Mechanical damageMechanical damage Chemical damageChemical damage Bacterial damageBacterial damage Thermal damageThermal damage Ultraviolet radiationUltraviolet radiation DesiccationDesiccation

Aids in heat regulationAids in heat regulation Aids in excretion of urea and uric acidAids in excretion of urea and uric acid Synthesizes vitamin DSynthesizes vitamin D

Skin StructureSkin Structure EpiEpidermis – outer layerdermis – outer layer

Stratified squamous Stratified squamous epitheliumepithelium

Often keratinized Often keratinized (hardened by keratin)(hardened by keratin)

DermisDermis Dense connective tissueDense connective tissue

Hypodermis Hypodermis (Subcutaneous Tissue)(Subcutaneous Tissue)

Below the dermisBelow the dermis Not part of the skinNot part of the skin Anchors skin to Anchors skin to

underlying organsunderlying organs Composed mostly of Composed mostly of

adipose tissueadipose tissue

Layers of the EpidermisLayers of the Epidermis1.1. Stratum basaleStratum basale

Cells undergoing mitosisCells undergoing mitosis Lies next to dermisLies next to dermis

2.2. Stratum spinosumStratum spinosum3.3. Stratum granulosumStratum granulosum4.4. Stratum lucidumStratum lucidum

Occurs only in thick skinOccurs only in thick skin

5.5. Stratum corneumStratum corneum Shingle-like dead cellsShingle-like dead cells

DermisDermis Two layersTwo layers

Papillary layerPapillary layer Projections called dermal papillae (fingerprints!)Projections called dermal papillae (fingerprints!) Pain receptorsPain receptors Capillary loopsCapillary loops

Reticular layerReticular layer Blood vesselsBlood vessels GlandsGlands Nerve receptorsNerve receptors

MelaninMelanin

Pigment produced by Pigment produced by melanocytesmelanocytes Amount produced depends on genetics Amount produced depends on genetics

and sun exposureand sun exposure Yellow, brown, black Yellow, brown, black

colorcolor Found in Found in stratum stratum

basalebasale

Normal Skin Normal Skin DeterminantsDeterminants MelaninMelanin

Yellow, brown or black pigmentsYellow, brown or black pigments

CaroteneCarotene Orange-yellow pigment from some vegetablesOrange-yellow pigment from some vegetables

HemoglobinHemoglobin Red coloring from blood cells in dermis Red coloring from blood cells in dermis

capillariescapillaries Oxygen content determines the extent of red Oxygen content determines the extent of red

coloringcoloring

SWEAT GLANDSSWEAT GLANDS

aka aka sudoriferoussudoriferous glands glands Found over entire skin Found over entire skin

surface except nipples and surface except nipples and part of external genitaliapart of external genitalia

> 2.5 > 2.5 millionmillion per person per person

Eccrine sweat glandsEccrine sweat glands More numerous, Located More numerous, Located

EVERYWHERE!EVERYWHERE! Abundant on Abundant on palms, soles of palms, soles of

feet and foreheadfeet and forehead secretory part of gland coiled in secretory part of gland coiled in

dermisdermis Duct extends to open in a Duct extends to open in a “pore”“pore”

Apocrine sweat Apocrine sweat glandsglands Located in Located in armpit and genitalarmpit and genital areas areas Begin to function at Begin to function at pubertypuberty under under

influence of androgensinfluence of androgens Thought to play role in sexual Thought to play role in sexual

attraction (scent glands in animals)attraction (scent glands in animals) Secrete fatty acids and proteins Secrete fatty acids and proteins

causing a yellowish colorcausing a yellowish color OdorlessOdorless, but bacteria feast on , but bacteria feast on

secretions giving musky odor secretions giving musky odor

Sweat and Its FunctionSweat and Its Function Composition

Mostly water plus salts (NaCl) Some metabolic waste (urea, ammonia, uric

acid) Acidic pH 4-6, inhibits bacteria Fatty acids and proteins (apocrine only)

Function Helps dissipate excess heat Excretes waste products Acidic nature inhibits bacteria growth

SEBACEOUSSEBACEOUS

GLANDSGLANDS                                                                                 

WHAT ARE THEY?WHAT ARE THEY? aka aka oil glandsoil glands secrete an oily substance secrete an oily substance

called called sebumsebum sebum is produced within sebum is produced within

specialized cells and is specialized cells and is released as these cells burst;released as these cells burst;

sebaceous glands are thus sebaceous glands are thus classified as classified as holocrineholocrine glands glands..

Sebum is a Sebum is a mixture of fat and mixture of fat and debris of dead fat-producing cellsdebris of dead fat-producing cells. . These cells are constantly These cells are constantly replaced by new growth at the replaced by new growth at the base of the glands. base of the glands.

sebum is deposited on the hairs sebum is deposited on the hairs inside the follicles and brought up inside the follicles and brought up to the surface of the skin along to the surface of the skin along the hair shaft. the hair shaft.

In hairless areas, the sebum In hairless areas, the sebum surfaces through ducts or poressurfaces through ducts or pores

Sebum acts to Sebum acts to protect and protect and waterproof hairwaterproof hair and skin,and skin, and and keep them from becoming keep them from becoming dry, brittle, and cracked. dry, brittle, and cracked.

It can also inhibit the growth It can also inhibit the growth of microorganisms on skin of microorganisms on skin since it since it contains contains antimicrobial substancesantimicrobial substances

Found everywhere on Found everywhere on the body except the body except the the palms of the hands palms of the hands and soles of the feet.and soles of the feet.

At the rim of the eyelids are a At the rim of the eyelids are a specialized form of sebaceous specialized form of sebaceous gland that secrete sebum into gland that secrete sebum into the tears coating the eye to the tears coating the eye to prevent evaporation.prevent evaporation.

The sebaceous glands of a The sebaceous glands of a human fetushuman fetus in uteroin utero secrete a substance called secrete a substance called vernix caseosavernix caseosa, a "waxy" , a "waxy" or "cheesy" white or "cheesy" white substance coating the skin substance coating the skin of newbornsof newborns

The The activity of the activity of the sebaceous glands sebaceous glands increases during pubertyincreases during puberty because of heightened because of heightened levels of androgens (sex levels of androgens (sex hormones).hormones).

Overactive Overactive sebaceous sebaceous glands can glands can cause skin cause skin problems problems such as such as acneacne..

The extreme use of The extreme use of anabolic steroidsanabolic steroids by by bodybuilders for muscle bodybuilders for muscle gain tend to stimulate the gain tend to stimulate the sebaceous glands which sebaceous glands which can cause acne.can cause acne.

A blocked sebaceous gland A blocked sebaceous gland can result in a can result in a sebaceous cystsebaceous cyst..

Dry skin is caused by Dry skin is caused by underactive oil glands underactive oil glands

as we get older, as our bodies as we get older, as our bodies don't produce these natural oils don't produce these natural oils so effectively. so effectively.

Babies and young children are Babies and young children are also often susceptible to dry skin also often susceptible to dry skin because the sebaceous glands because the sebaceous glands haven't developed properly. haven't developed properly.

Appendages of the SkinAppendages of the Skin HairHair

Produced by hair Produced by hair bulbbulb

Consists of hard Consists of hard keratinized keratinized epithelial cellsepithelial cells

MelanocytesMelanocytes provide pigment provide pigment for hair colorfor hair color

Figure 4.7c

Hair AnatomyHair Anatomy

Central medullaCentral medulla Cortex surrounds Cortex surrounds

medullamedulla Cuticle on outside of Cuticle on outside of

cortexcortex Most heavily Most heavily

keratinizedkeratinized

Figure 4.7b

Associated Hair Associated Hair StructuresStructures

Hair follicleHair follicle Dermal and epidermal Dermal and epidermal

sheath surround hair rootsheath surround hair root

Arrector pilliArrector pilli Smooth muscleSmooth muscle Lifts hair uprightLifts hair upright, ,

““goosebumpsgoosebumps””

Sebaceous glandSebaceous gland Sweat glandSweat gland

Figure 4.7a

Appendages of the SkinAppendages of the Skin

NailsNails Scale-like modifications of the Scale-like modifications of the

epidermisepidermis Heavily keratinizedHeavily keratinized

Stratum basaleStratum basale extends beneath the extends beneath the nail bednail bed Responsible for growthResponsible for growth

Lack of pigment makes them colorlessLack of pigment makes them colorless

Nail StructuresNail Structures

Free edgeFree edge BodyBody Root of nailRoot of nail Eponychium Eponychium

– proximal – proximal nail fold that nail fold that projects onto projects onto the nail bodythe nail body

Figure 4.9

Skin Homeostatic Skin Homeostatic ImbalancesImbalances

InfectionsInfections Athletes footAthletes foot

Caused by fungal infectionCaused by fungal infection

Boils and carbunclesBoils and carbunclesCaused by bacterial infectionCaused by bacterial infection

Cold soresCold soresCaused by virusCaused by virus

Skin Homeostatic Skin Homeostatic ImbalancesImbalances

Infections and allergiesInfections and allergies Contact dermatitisContact dermatitis

Exposures cause allergic reactionExposures cause allergic reaction

ImpetigoImpetigo Caused by bacterial infectionCaused by bacterial infection

PsoriasisPsoriasis Cause is unknownCause is unknown Triggered by trauma, infection, stressTriggered by trauma, infection, stress

BURNS BURNS

AND AND

SKIN SKIN CANCERSCANCERS

BURNSBURNS

BURNSBURNSWhat are they?What are they?What causes them?What causes them?

A burn is A burn is damage to your damage to your body's tissues caused by body's tissues caused by heat, chemicals, heat, chemicals, electricity, sunlight or electricity, sunlight or radiation. radiation.

Scalds from hot liquids Scalds from hot liquids and steam, building and steam, building fires and flammable fires and flammable liquids and gases are liquids and gases are the the most common most common causescauses of burns. of burns.

There are There are three types of three types of burnsburns depending on how depending on how severe the burn is and its severe the burn is and its damage to underlying damage to underlying tissues:tissues:

First degreeFirst degree Second degreeSecond degree Third degreeThird degree

Rule of NinesRule of Nines

Way to determine Way to determine the extent of the extent of burnsburns

Body is divided Body is divided into 11 areas for into 11 areas for quick estimationquick estimation Each area Each area

represents about represents about 9%9%

First-degree burnsFirst-degree burns

damage only thedamage only the outer outer layer of skin-layer of skin-thethe epidermis epidermis

Only symptom is Only symptom is redness redness of skinof skin

are are painfulpainful

Example: sunburnExample: sunburn

Second-degree burnsSecond-degree burns damage the damage the epidermis epidermis

andand the the dermisdermis Causes Causes blistersblisters to form as to form as

epidermis epidermis separatesseparates from from the dermisthe dermis

Also Also painfulpainful

Second Second degree degree burnsburns

Third-degree burnsThird-degree burns

damage or destroy damage or destroy both layers both layers of skin and tissues of skin and tissues underneathunderneath

patients often require patients often require skin skin graftsgrafts

usually usually painless painless because the because the nerve endingsnerve endings that supply that supply pain sensation pain sensation areare destroyeddestroyed

Third degree burnsThird degree burns

Burns can cause swelling, Burns can cause swelling, blistering, scarring and, in serious blistering, scarring and, in serious cases, shock and even death.cases, shock and even death.

Swelling and blistering come from Swelling and blistering come from fluids seeping out of the blood fluids seeping out of the blood vesselsvessels

This fluid loss creates one of the This fluid loss creates one of the greatest dangers from burns-greatest dangers from burns-fluid fluid lossloss and and dehydration.dehydration.

Fluid loss can be so great as Fluid loss can be so great as to lead to depletion of blood to lead to depletion of blood volume and shock and volume and shock and dangerously low blood dangerously low blood pressurepressure

Death is likely if the fluids Death is likely if the fluids are not replenished (are not replenished (IV fluid IV fluid replacementreplacement with isotonic with isotonic saline or plasma)saline or plasma)

Another great danger Another great danger of burns is of burns is infectioninfection because they damage because they damage your skin’s protective your skin’s protective barrier. Antibiotic barrier. Antibiotic creams can prevent or creams can prevent or treat infectionstreat infections.. ..

11stst and 2 and 2ndnd degree degree burns can heal over burns can heal over time without skin time without skin grafts since there is grafts since there is enough underlying skin enough underlying skin to repair the skin.to repair the skin.

After a third-degree After a third-degree burn, burn, skinskin or or synthetic synthetic graftsgrafts may be needed may be needed to cover exposed tissue to cover exposed tissue and encourage new skin and encourage new skin to grow. to grow.

This is as good as it will ever get. These scars are for life!

SKIN SKIN CANCERSCANCERS

Basal Cell CarcinomaBasal Cell Carcinoma

Least malignant but MOST COMMONLeast malignant but MOST COMMON Sun exposed areasSun exposed areas Invade the dermis and hypodermisInvade the dermis and hypodermis

Squamous Cell carcinomaSquamous Cell carcinoma

Scaly, reddend papuleScaly, reddend papule Sun-induced, metastasizes to lymph nodesSun-induced, metastasizes to lymph nodes

Malignant MelanomaMalignant Melanoma

Cancer of MelanocytesCancer of Melanocytes Only 5% of cancers, but increasingOnly 5% of cancers, but increasing MOST DEADLY (survival 50%)MOST DEADLY (survival 50%) Some develop from molesSome develop from moles

ABCD’sABCD’s A= AsymmetryA= Asymmetry

2 sides do not match2 sides do not match

B= Border IrregularityB= Border Irregularity Not smooth, indentationsNot smooth, indentations

C= ColorC= Color Different colors: reds, tans, blacks, brownDifferent colors: reds, tans, blacks, brown

D= DiameterD= Diameter larger than 6mmlarger than 6mm

E= EvolutionE= Evolution