5 integumentary system

7/23/2019 5 Integumentary System

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M A R I E J I M D I A N E O . P A Y O T , R M T , M S M T

INTEGUMENTARY

SYSTEM



SKIN OR CUTANEOUS MEMBRANE

• “in” – inward

• “tegere” – to cover

• Skin, hair, glands, nails, and sensory receptors

• Covers the external surface of the body



INTEGUMENTARY SYSTEM VS ANY

OTHER SYSTEMS

• “The appearance of our

skin frequently determines

the initial impression we

make on others.”



SKIN AS AN ORGAN

• Largest organ of the body

• 7,600 sq cm (3,000 sq in) – adult

• Approximately 7% body weight

• Thickness: 1.5 mm (average)

• Thickest: 6 mm (soles and palms)

• Thinnest: 0.5 mm (eyelids, external genitalia, ear drum)

• Texture

• Rough or callous: elbows and knuckles

• Soft and sensitive: eyelids



LAYERS OF SKIN

• Two Main Parts• Epidermis – epithelial tissue

• Dermis – connective tissue

• Hypodermis – subcutaneouslayer; not part of the skin;areolar and adipose tissue

• Storage depot for fat

• Contains blood vessels

• Contain nerve endings



EPIDERMIS

• Superficial protective layer

• Derived from ectoderm

• Stratified squamous

epithelium

• All but the deepest layersare composed of dead

cells.

• Keratinization – new cells(with keratin) push old cells

to surface



CELLS OF THE EPIDERMIS

•Keratinocytes (90%)• Arranged in 4 or

5 layers

• Keratin – tough

fibrous protein• Resemble flat

dead scales




• Melanocytes (8%)

• Melanin – skin

color; protectionagainst UV light

• Amount

produced isdetermined by

genetics, UV light

and hormones




• Merkel cells• Sensory receptor

cells

• Consist of tactile

disc and neuron• Tactile (touch)

reception

• Langerhans

cells• Immune

responses

• Epidermalmacrophages

• Ingest bacteria



EPIDERMIS



LAYERS OF THE EPIDERMIS

•Stratum basale• Deepest; attached to

dermis• Desmosomes &

hemidesmosomes

• A row of cuboidal or

columnar

keratinocytes

• Mitotic divisions –

every 19 days

•

10-25% melanocytes




•Stratum spinosum• 8-10 layers of many-

sided keratinocytes

• Spiny extensions ofcells

• Strength and flexibility

•

Melanin granules andLangerhans’ cells are

abundant• Melanin taken up by

keratinocytes and protectsthe nucleus




• Stratum granulosum• 3-4 flattened rows of cells

• Drastic changes inkeratinocyteappearance

• Keratohyaline – chemicalprecursor to keratin

• Lamellated bodies• Water-proofing

• Epithelial cells above thelayer die – too far fromthe dermis




•Stratum lucidum• Clear layer

•

Few rows of flat,dead keratinocytes

• Nuclei, organelles,

cell membrane – not

visible• Lips, soles and palms




• Stratum corneum• Keratinized cells

• 25-30 layers – flattened,scale-like cells

• Protects the skin

• Protective adaptation:drying and flattening

• Friction stimulates additionalmitotic activity in basale andspinosum: callus

• Dandruff: flaking off scalp



EPIDERMIS



SKIN COLORATION

• Melanin

• Brown-black pigment

• Production and distribution

• Protects basal layer against UV

• Tanning

• Albinism

• Normal number of cells

• Lacks tyrosinase (tyrosine to

melanin)• Hereditary

• Freckles

• aggregated patches ofmelanin



SKIN COLORATION

• Vitiligo

• White spots

• Lack of cells in localareas

• Liver spots

• Exposed portions

• Brown, plaque-like

growths• Carotene

• Yellow-orange

• Corneum and

dermis



SKIN COLORATION

• Hemoglobin

• Pinkish-red

• Erythema

• Increased bloodflow

• Pale skin

• Decreased bloodflow



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TANNING AND SUNBURNS

• Exposure to UV light stimulates melanocytes to

increase production of melanin

• Melanin builds up to help protect skin against UV

radiation (tan)

• A sunburn is the skin reacting to UV exposure

• UV light causes elastic fibers to clump and

become leathery

• UV light can alter DNA in cells causing them to

mutate (cancer)



24

SKIN COLOR AND DISEASE

• Redness:

fever, hypertension,inflammation, allergies

• Pallor:

anemia or low blood pressure• Jaundice:

liver disorder (yellow)

• Bronzing:

Addison’s disease (kidneydisease)

• Bruising:

broken blood vessels



DERMIS

• Dense connective

tissue: collagen

and elastic fibers

• Fibroblasts, nerve

endings, smooth

muscle, glands,

blood vessels, and

hair follicles



LAYERS OF THE DERMIS

• Papillary Layer

• Areolar connectivetissue

• Collagen andelastic fibers

• Contains bloodvessels

•Nutrients

• Remove wastes

• Regulates bodytemperature



DERMIS: PAPILLARY LAYER

• Dermal Papillae

• Projections that

extend to

epidermis

• Ridges

• Fingerprints

• Footprints• Genetically

determined



LAYERS OF THE DERMIS

• Reticular Layer

• Deepest

• 80% of dermis

• Dense collagenousconnective tissue

• Collagen: strength

• Elastin: recoil

• Striae (stretchmarks)

• Skin is overstretchedand the dermisruptures



DERMIS

• Reticular layer – Elastin and

collagen fibersare orientedmore in onedirection than in

others andproducecleavage, ortension, lines



HYPODERMIS

• Adipose tissue

• Heat insulator and fatstorage

• Increases as you gainweight

• Areolar connective

tissue

• Allows skin to bebound with muscles

• Large blood vessels

•

Arteries and veins



ACCESSORY STRUCTURES OF

THE SKIN

HAIR , SK IN GLANDS AND NAILS



HAIR

• Protection

• Scalp, nostrils,

brows, external

genitalia

• Thread of fused,

dead, keratinized

epidermal cells• Shaft – superficial

• Root – into the

dermis



HAIR

• Lanugo (fetal hair) isreplaced near thetime of birth by

terminal hairs (scalp,eyelids, and eyebrows)and vellus hairs

• At puberty, vellus hairscan be replaced withterminal hairs



HAIR

• Hair follicle

• External and internalroot sheaths

• Hair bulb• Papilla – contains

blood vessels;nourishment

• Matrix – producesnew hair; cell division

• Smooth muscle

• Goosebumps



HAIR



39

HOW IS HAIR PRODUCED?

• Hair is produced in hair bulb

• Hair bulb rests on blood vessels to supply itwith nutrients

•Hair grows longer as cells are added to baseof hair bulb



40

HAIR FACTS

• Testosterone and good nutrition promote hair

growth

•

Growth occurs in cycles: active and resting• Scalp hair grows for 3 years and rests for 1 year

• Eyelashes grow for 30 days and rest for 105 days

• We lose about 90 scalp hairs/day

• Grey hair is the loss or fading of melanin

• Male pattern baldness is from the loss of the hair

follicle



HAIR OR PILI

• Melanin – synthesized by melanocytesin the matrix of the bulb

• Dark-colored – brown to black

• Blonde and red – yellow to red• Iron and more sulfur

• Gray – decline melanin synthesis

• White – accumulation of air bubbles inthe hair shaft

• Hirsutism – excessive body hair• androgens

• Androgenic alopecia• Male-pattern baldness



HAIR



GLANDS

• Single or groups ofepithelial cells thatsecrete a substance

• Sebaceous Glands

• Sudoriferous Glands•

Eccrine sweat glands• Apocrine sweat glands

• Ceruminous Glands

• Mammary Glands



SUDORIFEROUS GLANDS

• Sweat glands

• Release sweat, orperspiration intohair follicles, ontothe skin surface(pores)

• Eccrine – morecommon

• Apocrine – simple,coiled tubular• Odorless; bacteria

(body odor)



SUDORIFEROUS

GLANDS

FEATURES ECCRINE GLAND APOCRINE GLANDDistribution Widely distributed

(forehead, palms, soles)Axilla, groin, areolae,bearded regions of the face

Secretory portion Dermis Hypodermis

Excretory portion Epidermis Hair follicle

Nature of secretion Water, ions, urea, uricacid, amino acid,glucose, lactic acid

Slightly viscous, milky oryellowish; lipids and proteins

Function Regulates bodytemperature

Emotional stress and sexualexcitement; cold sweat

Onset of function After birth During puberty



SEBACEOUS GLANDS

• Oil glands

• Increases duringadolescence

• Connected to hair follicles

• Secreting portions – dermis

• None in the palms and soles

•

Secrete sebum• Keeps hair from drying out

• Prevents excessive evaporation ofwater from the skin

• Keeps the skin soft

•Inhibits growth of certain bacteria



SEBACEOUS GLANDS

• Whiteheads

• Blackheads – enlarged

glands in the face• Color due to melanin and

oxidized oil, not dirt

• Pimples or boils – sebumis nutritive to bacteria

• Acne – inflammation ofglands



CERUMINOUS GLANDS

• External auditory

canal

• Cerumen – secretion

of ceruminous andsebaceous• Earwax

• Plus hairs of the externalauditory canal – stickybarrier

• Waterproofs the canal

• Prevents bacteria and fungifrom entering



Eccrine

sweat gland

Sebaceous gland

Arrector pili

(smooth muscle)

Duct of eccrine

sweat gland

Sweat pores

Apocrine

sweat gland

Hair bulb

Hair follicle

Duct of

apocrine

sweat gland



NAILS

• Plates of tightlypacked, hard, dead,keratinized cells ofepidermis

• Grasp and manipulatesmall objects

• Provide protection tothe ends of fingers and

toes• Allows to scratch

various parts of thebody



NAILS

• Nail body – visible• Pink – blood

capillaries

• Free edge –

extends pastthe end of thefinger or toe



NAILS

• Nail root

• Covered by skin

• Nail matrix – superficial cells

divide by mitosis

• Nail bed – attaches to nail; distal

to nail matrix

• Lunula – whitish (vascular tissue)

semilunar; part of nail matrix

• Cuticle – stratum corneum

extending to nail body



NAILS



FUNCTIONS OF THE SKIN

• Regulates bodytemperature• Sweating promotes evaporation

•

High temperature• Increased sweat (lowers body

temperature)

• Vasodilation – larger surface area inblood vessels

• Low temperature• Decreased sweat (conserves heat)

• Vasoconstriction – smaller surfacearea in blood vessels




• ProtectionChemical Factors

• Oily sebum – prevents hairfrom drying

• Acidic pH of perspiration – retards growth of microbes

• Sweat is slightly hypertonic – flush off bacteria

• Melanin – protection againstUV light




• ProtectionPhysical Factors

• Stratified squamousepithelium – preventsbacteria invasion

• Keratinized cells – physicalbarrier against invasion

Biological Factor

• Macrophage – destroybacteria and foreignsubstances




• Excretion• Ammonia, urea, and excessive

salt

• Sweating

• Absorption•

Oxygen and carbon dioxide• Small amounts of UV light




• Cutaneoussensations• Arise in the skin

• Receptors for:

• Pain – free nerveendings

• Temperature – hot

and cold receptors• Touch – Merkel’s disks

and Meissner’scorpuscles

• Pressure – Pacinian

corpuscles




• Synthesis of Vitamin D• Exposure of skin to UV light

activates Vitamin D

•Vitamin D is converted tocalcitriol (active hormone)in the liver and kidney

• Metabolism of calcium

and phosphorus



VITAMIN D PRODUCTION

1. UV light causes skin to produce a precursor

molecule of vitamin D

2. Precursor is carried by blood to liver where it

is modified3. Next to kidneys where it is modified again

to form active vitamin D

• Vitamin D can also be ingested through fish

oils, fortified milk, eggs, and butter.• Vitamin D stimulates intestine to absorb

calcium and phosphate (bone growth andmuscle function)



AS A DIAGNOSTIC TOOL

• Cyanosis

• Jaundice

• Rashes and lesions

• Condition of skin,

hair, and nails

• Vitamin A deficiency

– sandpaper textureof the skin

• Iron deficiencyanemia – spoon-shaped nails



64

CLASSIFICATION OF BURNS

• 1st degree:- damages only epidermis

- redness, slight swelling, pain

- heals within 2-3 days (usually no scar)- includes sunburns or exposure to cold

• 2nd degree:- damages epidermis and upper dermis

- redness, swelling, pain, blisters

- heals in 2 weeks with some scarring



65

•3rd degree:

- destroys epidermis and dermis

- burned areas are cherry red

to black- nerve endings are destroyed

- skin graft might be necessary



Full-

thickness

Third-degree

Subcutaneous

tissue

Dermis

Epidermis

Second-degree

Partial-

thickness

First-degree



RULE OF NINES

• Estimates the severity of burns

• Divides body into areas thatare ~ 9%, or multiples of 9%, ofthe total body area

• Younger patients are different

• Burns critical if:• Over 25% of the body has

second-degree burns

• Over 10% of the body hasthird-degree burns

• There are third-degreeburns on face, hands, orfeet



SKIN CANCER

• Most common cancer

• Mainly caused by UV light exposure

• Fair-skinned people more prone

• Prevented by limiting sun exposure and using

sunscreens

• UVA rays cause tan and is associated with

malignant melanomas• UVB rays cause sunburns

• Sunscreens should block UVA and UVB rays

68



BASAL CELL CARCINOMA

• Least malignant and most common skin cancer

• Stratum Basale cells proliferate and invade thedermis and hypodermis

• Slow growing and do not often metastasize

•

Can be cured by surgical excision in 99% of thecases



SQUAMOUS CELL CARCINOMA

•

Arises from keratinocytes of Stratum Spinosum• Arise most often on scalp, ears, and lower lip

• Grows rapidly and metastasizes if not removed

• Prognosis is good if treated by radiation therapy or

removed surgically



MELANOMA

•

Cancer of melanocytes is the most dangerous typeof skin cancer because it is:

• Likely to metastasize

• Resistant to chemotherapy



MELANOMA

• Characteristics (ABCD rule)• A: Asymmetry; the two sides of the pigmented

area do not match

• B: Border is irregular and exhibits indentations

• C: Color (pigmented area) is black, brown, tan,and sometimes red or blue

• D: Diameter is larger than 6 mm (size of a pencileraser)

• Treated by wide surgical excisionaccompanied by immunotherapy

• Chance of survival is poor if the lesion is over4 mm thick



AGING AND THE INTEGUMENTARY




SYSTEM

1. Collagen fibers (dermis)• Decrease in number, stiffen, break apart,

disorganize

2. Elastic fibers

3. Fibroblasts (produce collagen &elastic fibers)• Decrease in number

• Wrinkles

4. Langerhans cells and macrophages• Decrease in number; less-efficient phagocytes

5. Sebaceous glands• Decrease size leads to dry and broken skin;

susceptible to infection





SYSTEM

6. Production of sweat• Diminishes; heat stroke

7. Melanocytes• Decreasing in number; gray hair; increasing

in size (age spots)

8. Hair follicles

• Stop producing hairs; hair loss

9. Walls of blood vessels (dermis)

• Thicker, less permeable, lost adipose

tissue

10.Migration of cells from basal toepidermal is slow

• Skin heals poorly





SYSTEM



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