IntegumentarIntegumentary Systemy System

(Hypodermis)

Integumentary SystemIntegumentary System

Skin

Hair

Nails

Associated Structures (vessels, nerves, glands)

MembranesMembranes

Epithelial membranesEpithelial membranes– CutaneousCutaneous– MucousMucous– Serous Serous

Parietal vs visceralParietal vs visceral Pleura, pericardium, peritoneumPleura, pericardium, peritoneum

Integumentary SystemIntegumentary System Skin (cutaneous membrane)

Main layers – superficial to deep

Epidermis

Dermis

Hypodermis

-not always

considered

part of skin(Hypodermis)

Functions of SkinFunctions of Skin Protection

Sensation

Movement without energy

Excretion

Vitamin D production – needed to absorb calcium

Sun+Skin Vit D blood kidney/liver calcitriol blood regulates calcium & phosphorous

Immunity

Healing Wounds

Body temperature homeostasis

vasoconstriction & vasodilation

Skin StructureSkin Structure

EpidermisEpidermis

Epidermis – outer layer

Keratinized stratified squamous epithelium

Avascular (hardened by keratin)

Renews itself ~ every 45 days

Epidermis – cell typesEpidermis – cell types Keratinocytes

produce keratin – waterproofing protein

Originate in deeper layers & get pushed to surface – becomes keratin filled & dies

Connected to each other by desmosomes & tight junctions

Cell production & keratinization are accelerated in areas of friction

Callus – thickened skin

Epidermis – cell typesEpidermis – cell types• Melanocytes

• Produce melanin • Prevents DNA mutation from the UV

radiation• UV increases melanin production• Same number in everyone, but

different amount of pigment produced• Accumulation of melanin results in

freckles and moles

Epidermis – Skin ColorEpidermis – Skin Color

Determined by three factors: Types of pigments present

Melanin – brown, black, or yellow pigment

Carotene

Hemoglobin

Blood circulation

Stratum corneum thickness

Orange-yellow pigment from some vegetables

Vitamin A precurser – vitamin A forms retinal which is needed for sight

Accumulates in adipose and stratum corneum cells

Red, oxygen-carrying pigment in erythrocytes

More obviously detected in fair skin

Skin as a DiagnosticSkin as a Diagnostic Skin color is influenced by emotional & disease states:

You should know the states that cause these.

Cyanosis – bluish color - lack of oxygen

Erythema – redness – heat, inflammation, fever

Albinism – genetically black, but white – no melanin produced from melanocytes

Pallor – paleness – lack of blood flow

Jaundice – yellowish color – liver damage; accumulation of bilirubin

Bronzing – bronze (tan) – Addison’s disease

Hematomas – black & blue – blood under skin

5 strata of the Epidermis – Deep to Superficial5 strata of the Epidermis – Deep to Superficial Stratum basale

highly mitotic (produces new skin layer)

~ 25% melanocytes

Stratum spinosum Slightly mitotic

Contains Langerhan’s macrophages

Several layers of many sided cells (looks spiny) Stratum granulosum

Also contains Langerhans cell

contains keratohyalin (helps form keratin)

Stratum lucidum

ONLY found in thicker epidermis – palms, soles, callus

Completely keratinized (and dead!)

contains closely packed, clear cells that contain gel-like substance eleiden

5 strata of the Epidermis5 strata of the Epidermis Stratum corneum

Outermost layer

Also completely keratinized

Dead cells

Tough, waterproofing protection

DermisDermis Middle layer of skin Contains hair folllicles, glands, nerves,

vessels, muscle All four tissue types present Mainly strong, flexible CT - Two layers

DermisDermis Papillary layer

Contains Areolar CT Dermal papillae

Indent into epidermisforms fingerprintsImportant for gripContains blood vesselsMeissner’s Corpuscles – nerve (touch) receptors

DermisDermis Reticular layer

Dense irregular CT contains blood vessels, nerves,

glands, adiposePacinian Corpuscles – nerve endings

responsible for sensitivity to deep pressure touch and high frequency vibration

Collagen – prevents overstretching and tearing of skin

Elastin – allows skin to stretchstretch marks – dermal tears

HypodermisHypodermis

Not usually considered part of the skin

Also called subcutaneous layer

Site of subcutaneous injections – absorbed directly into blood stream

Anchors skin to underlying organs, shock absorption, insulation

Composed mostly of adipose tissue

Very vascular

Skin AppendagesSkin Appendages

Appendages of the SkinAppendages of the SkinHair Minor protective functions (retain heat, decrease sunburn,

eyelashes protect eyes)

Structure

shaft – projects from skin

follicle – extends into dermis

root – lies within the follicle

bulb – contains CT, vessels and nerves

sebaceous gland – lubricates hair

arrector pili muscle – attached to follicle and contracts to move hair (hair growth, goosebumps)

HairHair

Appendages of the SkinAppendages of the Skin Hair Growth

influenced by: (in this order)

nutrition - main influence

hormones

blood flow

baldness ( alopecia )

male pattern baldness - sex linked recessive genetic trait

thinning – can be caused by medications, nutrition, stress, etc.

Hair Pigment caused by proportions of 3 melanin types

dark hair – true melanin

blonde and red – melanin with iron and sulfur

gray/white hair - melanin replaced by air bubbles in shaft

Appendages of the SkinAppendages of the SkinNails

Scale-like modifications of the epidermis

Heavily keratinized

Stratum basale extends beneath the nail bed to form nail matrix

Responsible for growth ( matrix region)

Lack of pigment makes them colorless

Lunula “little moon” – area of cell growth (white semicircle at base of nail)

Cuticle – area of skin that covers base of nail

Nail StructuresNail Structures

Sweat GlandsSweat Glands Eccrine glands

Widely distributed in skin: abundant on palms, soles, forehead

Sweat composition: mostly water with a slightly acidic 4-6 pH

Function: thermoregulation

• Apocrine glands Ducts empty into hair follicles Found mainly in anogenital & axillary region Begin to function at puberty due to hormones / pheromones Organic contents: Fatty acids and proteins – can have a

yellowish color that stains clothes Odor is from associated bacteria

Ceruminous glands Modified apocrine gland Found in outer 1/3 of ear canal Produce ear wax to trap “invaders”

Appendages of the SkinAppendages of the Skin Sebaceous glands

all over except palms and soles of feet

Produce oil for waterproofing

Lubricant for skin & kills bacteria

Most with ducts that empty into hair follicles

Glands are activated at puberty: stimulated by hormones

Acne – active infection of sebaceous glands

BurnsBurns

BurnsBurns Protein denaturation and cell death caused

by heat, electricity, UV radiation, or chemicals

2 main dangers

Dehydration–Loss of fluids & Electrolytes lead to:

Renal Shutdown

Circulatory shock

Infection

Skin (mechanical) barrier lost

Immune system depresses

Rules of NinesRules of Nines

Way to determine the extent of burns

Primary importance is to estimate fluids needed for rehydration

Body is divided into 11 areas for quick estimation

Each area represents about 9%

Rule of nines diagramRule of nines diagram

Partial Thickness BurnsPartial Thickness Burns

Slide 4.27Slide 4.27

First-degree burns Only epidermis is damaged Local redness, swelling, & pain Usually heal in 2-3 days (short time period)

with NO scarring

Partial Thickness BurnsPartial Thickness Burns Second degree burns

Epidermis and dermis & structures within dermis are damaged

Appearance of blisters of any size

Skin regeneration in

3-4 weeks with some scarring

There is a danger of infection

Full Thickness BurnsFull Thickness Burns Third-degree burns

Epidermis, Dermis, Hypodermis and all structures within are completely destroyed

Usually painless at site of burn due to destruction of sense receptors

Burn is gray-white, tan, brown, black, or deep cherry red

Surrounded by areas of 1st & 2nd degree burns that will be painful

Treatments are numerous but will involve skin grafting of some sort, fluid replacement and debridement

All degrees of burnsAll degrees of burns

Skin CancerSkin CancerSkin cancer is the most common type of Skin cancer is the most common type of

cancercancer

2 out of 5 cancers are skin cancers2 out of 5 cancers are skin cancers

Skin CancerSkin Cancer

Cancer – uncontrolled cell growth Caused by damage to the DNA usually

through chemicals or radiation Two types

Benign

Does not spread (encapsulated)

Malignant

Metastasized (moves) to other parts of the body

Skin Cancer TypesSkin Cancer TypesBasal cell carcinoma

Least malignant

Most common type (90% of skin cancers) Arises from stratum basale

cannot produce keratin

Boundary lost between dermis and epidermis

Seldom metastasizes – treated surgically or by radiation – 99% cure rate if caught early

Signs

Pale marks

Reddish patches

Round, smooth growth with raised edge

Shiny bumps

Sores that don’t heal

Basal Cell CarcinomaBasal Cell Carcinoma

Basal Cell CarcinomaBasal Cell Carcinoma

Skin Cancer TypesSkin Cancer Types Squamous cell carcinoma

2nd most common skin cancer

Highest risk – fair skin, light hair, blue/green eyes

Arises from stratum spinosum

Metastasizes to lymph nodes if left untreated

1500-2000 deaths in US per year

Early removal allows a good chance of cure

Signs are same as basal cell carcinoma

Squamous Cell CarcinomaSquamous Cell Carcinoma

Cumulative EffectsCumulative Effects

IMPORTANT TO KNOWIMPORTANT TO KNOW Basal cell & squamous cell Basal cell & squamous cell

carcinomas are due to cumulative carcinomas are due to cumulative effects of the sun’s radiation (or effects of the sun’s radiation (or chemical exposures as well)chemical exposures as well)

These tend to develop in ages 30-40s These tend to develop in ages 30-40s after years of daily sun exposureafter years of daily sun exposure

Skin Cancer TypesSkin Cancer Types Malignant melanoma

Least common

most deadly of skin cancers

Originates melanocytes

Metastasizes rapidly to lymph and blood vessels

Early detection is critical – see notes for survival rates

Intensive EffectsIntensive Effects

Malignant Melanoma tends to occur Malignant Melanoma tends to occur in younger ages (as well as older in younger ages (as well as older people)people)

It is due to brief intense exposures It is due to brief intense exposures (aka: sunburns)(aka: sunburns)

This is the most serious form of skin This is the most serious form of skin cancer and MUST be caught early to cancer and MUST be caught early to be treated successfully!be treated successfully!

ABCD RuleABCD Rule A = Asymmetry

Two sides of pigmented mole do not match B = Border irregularity

Borders of mole are not smooth C = Color

Different colors in pigmented area D = Diameter

Spot is larger then 6 mm in diameter (pencil eraser)

Mole starts growing/changing in size

Malignant Melanoma

MelanomasMelanomas

MelanomasMelanomas

PreventionPrevention Wear sunscreen whenever outside or cover upWear sunscreen whenever outside or cover up avoid midday sun between 10-2 and beware of avoid midday sun between 10-2 and beware of

reflected lightreflected light higher altitudes - every 1000 ft above sea level, higher altitudes - every 1000 ft above sea level,

radiation increases 4-5 %radiation increases 4-5 % Be cautious about tanning bedsBe cautious about tanning beds Medications - tetracycline (antibiotics), Retin A, Medications - tetracycline (antibiotics), Retin A,

birth control, antidepressants, birth control, antidepressants, diuretics, and anti-inflammatories cause diuretics, and anti-inflammatories cause

photosensitivityphotosensitivity avoid sunburnsavoid sunburns examine skin regularly - remember ABCD rule examine skin regularly - remember ABCD rule

– have full body check by dermatologist once – have full body check by dermatologist once a yeara year

Other Other Integumentary Integumentary

System disordersSystem disorders

Contact dermatitis (Ezcema)

Exposure to allergen/irritant (ie. poison ivy) cause allergic reaction

inflammation, red, itchy skin

not contagious

over the counter meds; sometimes Rx

Prevention by avoiding allergen/irritant

Blisters

Epidermal cell injury or separation of epidermis from dermis

Warts

Benign neoplasms, but can turn malignant

Contagious

Remove by freezing, drying, laser therapy,

chemicals

Boils

Bacterial infection that infects hair follicles

Large, inflamed, pus-filled lesions

TineaFungal infections (ringworm, jock itch, athlete’s foot)Reddish discoloration, scaling, crustingTreat with antifungal agentPrevent recurrence by keeping skin dry

ImpetigoCaused by bacterial infectionMostly childrenReddish discoloration turns into blisters

and yellowish crustsIf turns systemic, it is life threatening

PsoriasisCause is unknown, probably geneticTriggered by trauma, infection, stress

Cutaneous inflammation, scaly lesions Due to excessive rate of epithelial cell growth

UrticariaHivesRaised, red lesions caused by blood vessel leakageSevere itchingCauses (hypersensitivity, allergic reactions, physical irritants, systemic disease)

SclerodermaAutoimmuneAffects blood vessels and CTHard skin lesionsMore common in women

Decubitus ulcers“bedsores” / pressure soresLack of blood flow causes tissue damage

Acne * Clogged sebaceous follicles from abnormal shedding of skin cells * Bacteria build-up in sebaceous glands * Enhanced by hormones * Over the counter meds; sometimes Rx * Prevention

-avoid using oils, greasy moisturizers, facewash, and makeup-wash hands before applying makeup-use non-scented ordinary mild soap-keep hands away from face