Anatomy lab. 2 integumentary sys

Anatomy lab Al Azhar university Gaza

1. 11
Chapter 5Chapter 5
The Integumentary SystemThe Integumentary System
Skin and its Skin and its
accessory accessory
structuresstructures
–structurestructure
–functionfunction
–growth and repairgrowth and repair
–developmentdevelopment
–agingaging
–disordersdisorders

2. 22
General AnatomyGeneral Anatomy
A large organ A large organ
composed of all 4 composed of all 4
tissue typestissue types
22 square feet 22 square feet
1-2 mm thick1-2 mm thick
Weight 10 lbs.Weight 10 lbs.

3. The Integumentary SystemThe Integumentary System
Integument is skinIntegument is skin
Skin and its appendages make up the Skin and its appendages make up the
integumentary systemintegumentary system
A fatty layer (hypodermis) lies deep to itA fatty layer (hypodermis) lies deep to it
Two distinct regionsTwo distinct regions
–EpidermisEpidermis
–DermisDermis

4. Functions of skinFunctions of skin
ProtectionProtection
–Cushions and insulates and is waterproofCushions and insulates and is waterproof
–Protects from chemicals, heat, cold, bacteriaProtects from chemicals, heat, cold, bacteria
–Screens UVScreens UV
Synthesizes vitamin D with UVSynthesizes vitamin D with UV
Regulates body heatRegulates body heat
Prevents unnecessary water lossPrevents unnecessary water loss
Sensory reception (nerve endings)Sensory reception (nerve endings)

6. EpidermisEpidermis
Keratinized stratified squamous epitheliumKeratinized stratified squamous epithelium
Four types of cellsFour types of cells
–Keratinocytes – deepest, produce keratin (tough fibrous protein)Keratinocytes – deepest, produce keratin (tough fibrous protein)
–Melanocytes - make dark skin pigment melanin Melanocytes - make dark skin pigment melanin
–Merkel cells – associated with sensory nerve endings Merkel cells – associated with sensory nerve endings
–Langerhans cells – macrophage-like dendritic cellsLangerhans cells – macrophage-like dendritic cells
Layers (from deep to superficial)Layers (from deep to superficial)
–Stratum basale or germinativum – single row of cells attached to Stratum basale or germinativum – single row of cells attached to
dermis; youngest cellsdermis; youngest cells
–Stratum spinosum – spinyness is artifactual; tonofilaments Stratum spinosum – spinyness is artifactual; tonofilaments
(bundles of protein) resist tension(bundles of protein) resist tension
–Stratum granulosum – layers of flattened keratinocytes producing Stratum granulosum – layers of flattened keratinocytes producing
keratin (hair and nails made of it also)keratin (hair and nails made of it also)
–Stratum lucidum (only on palms and soles)Stratum lucidum (only on palms and soles)
–Stratum corneum – horny layer (cells dead, many layers thick)Stratum corneum – horny layer (cells dead, many layers thick)
(see figure on next slide)

8. Epithelium: layers (on left) and cell types (on right)Epithelium: layers (on left) and cell types (on right)

9. Remember…Remember…
Four basic types of tissueFour basic types of tissue
–Epithelium – epidermis just discussedEpithelium – epidermis just discussed
–Connective tissue - Connective tissue - dermisdermis
–Muscle tissueMuscle tissue
–Nervous tissueNervous tissue

10. DermisDermis
Strong, flexible connective tissue: your “hide”Strong, flexible connective tissue: your “hide”
Cells: fibroblasts, macrophages, mast cells, Cells: fibroblasts, macrophages, mast cells,
WBCsWBCs
Fiber types: collagen, elastic, reticularFiber types: collagen, elastic, reticular
Rich supply of nerves and vesselsRich supply of nerves and vessels
Critical role in temperature regulation (the Critical role in temperature regulation (the
vessels)vessels)
Two layers (see next slides)Two layers (see next slides)
–Papillary – areolar connective tissue; includes dermal Papillary – areolar connective tissue; includes dermal
papillae papillae
–Reticular – “reticulum” (network) of collagen and Reticular – “reticulum” (network) of collagen and
reticular fibersreticular fibers

11. *Dermis layers
*
*
*Dermal papillae

12. Epidermis and dermis of (a) thick skin and (b) thin skin
(which one makes the difference?)

13. 1313
OverviewOverview
2 Major layers of skin2 Major layers of skin
–epidermis is epidermis is
epithelial tissue onlyepithelial tissue only
–dermis is layer of dermis is layer of
connective tissue, connective tissue,
nerve & musclenerve & muscle
Subcutaneous tissue Subcutaneous tissue
(subQ or hypodermis) is (subQ or hypodermis) is
layer of adipose & layer of adipose &
areolar tissueareolar tissue
–subQ = subcutaneous subQ = subcutaneous
injectioninjection
–intradermal = within intradermal = within
the skin layerthe skin layer

14. 1414
Overview of EpidermisOverview of Epidermis
Stratified squamous Stratified squamous
epitheliumepithelium
Contains no blood vesselsContains no blood vessels
4 types of cells4 types of cells
5 distinct strata (layers) of 5 distinct strata (layers) of
cellscells

15. 1515
Cell types of the EpidermisCell types of the Epidermis
 Keratinocytes--90%Keratinocytes--90%
–produce keratinproduce keratin
 Melanocytes-----8 %Melanocytes-----8 %
–produces melanin pigmentproduces melanin pigment
–melanin transferred to other melanin transferred to other
cells with long cell cells with long cell
processesprocesses
Langerhan cellsLangerhan cells
–from bone marrowfrom bone marrow
–provide immunityprovide immunity
Merkel cellsMerkel cells
–in deepest layerin deepest layer
–form touch receptor with form touch receptor with
sensory neuronsensory neuron

16. 1616
Layers (Strata) of the EpidermisLayers (Strata) of the Epidermis
Stratum corneumStratum corneum
Stratum lucidumStratum lucidum
Stratum granulosumStratum granulosum
Stratum spinosumStratum spinosum
Stratum basaleStratum basale

17. 1717
Stratum BasaleStratum Basale
Deepest single layer of cells Deepest single layer of cells
Called stratum germinativumCalled stratum germinativum
Combination of merkel cells, Combination of merkel cells,
melanocytes, keratinocytes & melanocytes, keratinocytes &
stem cells that divide stem cells that divide
repeatedlyrepeatedly

18. 1818
Stratum SpinosumStratum Spinosum
8 to 10 cell layers held together 8 to 10 cell layers held together
by desmosomesby desmosomes
During slide preparation, cells During slide preparation, cells
shrink and look spinyshrink and look spiny
Melanin taken in by phagocytosis Melanin taken in by phagocytosis
from nearby melanocytesfrom nearby melanocytes

19. 1919
Stratum GranulosumStratum Granulosum
3 - 5 layers of flat dying 3 - 5 layers of flat dying
cellscells
Show nuclear Show nuclear
degenerationdegeneration
Contain dark-staining Contain dark-staining
keratohyalin granuleskeratohyalin granules
Contain lamellar granules Contain lamellar granules
that release lipid that that release lipid that
repels waterrepels water

20. 2020
Stratum LucidumStratum Lucidum
Seen in thick skin on Seen in thick skin on
palms & soles of feetpalms & soles of feet
Three to five layers of Three to five layers of
clear, flat, dead cellsclear, flat, dead cells
Contains precursor of Contains precursor of
keratinkeratin

21. 2121
Stratum CorneumStratum Corneum
25 to 30 layers of flat 25 to 30 layers of flat
dead cells filled with dead cells filled with
keratin and surrounded keratin and surrounded
by lipidsby lipids
Continuously shedContinuously shed
Barrier to light, heat, Barrier to light, heat,
water, chemicals & water, chemicals &
bacteriabacteria
Friction stimulates callus Friction stimulates callus
formationformation

22. 2222
Keratinization & Epidermal Keratinization & Epidermal
GrowthGrowth
Stem cells divide to produce keratinocytesStem cells divide to produce keratinocytes
As keratinocytes are pushed up towards the As keratinocytes are pushed up towards the
surface, they fill with keratinsurface, they fill with keratin
4 week journey unless outer layers removed 4 week journey unless outer layers removed
in abrasionin abrasion
Psoriasis = chronic skin disorderPsoriasis = chronic skin disorder
–cells shed in 7 to 10 days as flaky silvery scalescells shed in 7 to 10 days as flaky silvery scales
–abnormal keratin producedabnormal keratin produced

23. 2323
Skin GraftsSkin Grafts
New skin can not regenerate if stratum New skin can not regenerate if stratum
basale and its stem cells are destroyedbasale and its stem cells are destroyed
Skin graft is covering of wound with piece Skin graft is covering of wound with piece
of healthy skinof healthy skin
–autograft from selfautograft from self
–isograft from twinisograft from twin
–autologous skinautologous skin
transplantation of patients skin grown in culturetransplantation of patients skin grown in culture

24. 2424
DermisDermis
Connective tissue layer composed of collagen Connective tissue layer composed of collagen
& elastic fibers, fibroblasts, macrophages & & elastic fibers, fibroblasts, macrophages &
fat cellsfat cells
Contains hair follicles, glands, nerves & blood Contains hair follicles, glands, nerves & blood
vesselsvessels
Major regions of dermisMajor regions of dermis
–papillary regionpapillary region
–reticular regionreticular region

25. 2525
Papillary RegionPapillary Region
Top 20% of dermisTop 20% of dermis
Composed of loose CT & elastic fibers Composed of loose CT & elastic fibers
Finger like projections called dermal Finger like projections called dermal
papillaepapillae
FunctionsFunctions
–anchors epidermis to dermisanchors epidermis to dermis
–contains capillaries that feed epidermiscontains capillaries that feed epidermis
–contains Meissner’s corpuscles (touch) & free contains Meissner’s corpuscles (touch) & free
nerve endings (pain and temperature)nerve endings (pain and temperature)

26. 2626
Reticular RegionReticular Region
Dense irregular connective tissueDense irregular connective tissue
Contains interlacing collagen and elastic fibersContains interlacing collagen and elastic fibers
Packed with oil glands, sweat gland ducts, fat & hair Packed with oil glands, sweat gland ducts, fat & hair
folliclesfollicles
Provides strength, extensibility & elasticity to skinProvides strength, extensibility & elasticity to skin
–stretch marks are dermal tears from extreme stretchingstretch marks are dermal tears from extreme stretching
Epidermal ridges form in fetus as epidermis Epidermal ridges form in fetus as epidermis
conforms to dermal papillaeconforms to dermal papillae
–fingerprints are left by sweat glands open on ridgesfingerprints are left by sweat glands open on ridges
–increase grip of handincrease grip of hand

27. 2727
Skin Color Pigments (1)Skin Color Pigments (1)
Melanin produced in epidermis by melanocytesMelanin produced in epidermis by melanocytes
–same number of melanocytes in everyone, but differing same number of melanocytes in everyone, but differing
amounts of pigment producedamounts of pigment produced
–results vary from yellow to tan to black colorresults vary from yellow to tan to black color
–melanocytes convert tyrosine to melaninmelanocytes convert tyrosine to melanin
UV in sunlight increases melanin productionUV in sunlight increases melanin production
Clinical observationsClinical observations
–freckles or liver spots = melanocytes in a patchfreckles or liver spots = melanocytes in a patch
–albinism = inherited lack of tyrosinase; no pigmentalbinism = inherited lack of tyrosinase; no pigment
–vitiligo = autoimmune loss of melanocytes in areas of the vitiligo = autoimmune loss of melanocytes in areas of the
skin produces white patchesskin produces white patches

28. 2828
Skin Color Pigments (2)Skin Color Pigments (2)
 Carotene in dermisCarotene in dermis
–yellow-orange pigment (precursor of vitamin A)yellow-orange pigment (precursor of vitamin A)
–found in stratum corneum & dermisfound in stratum corneum & dermis
 HemoglobinHemoglobin
–red, oxygen-carrying pigment in blood cellsred, oxygen-carrying pigment in blood cells
–if other pigments are not present, epidermis is if other pigments are not present, epidermis is
translucent so pinkness will be evidenttranslucent so pinkness will be evident

29. 2929
Skin Color as Diagnostic ClueSkin Color as Diagnostic Clue
JaundiceJaundice
–yellowish color to skin and whites of eyesyellowish color to skin and whites of eyes
–buildup of yellow bilirubin in blood from liver buildup of yellow bilirubin in blood from liver
diseasedisease
CyanoticCyanotic
–bluish color to nail beds and skinbluish color to nail beds and skin
–hemoglobin depleted of oxygen looks purple-bluehemoglobin depleted of oxygen looks purple-blue
ErythemaErythema
–redness of skin due to enlargement of capillaries redness of skin due to enlargement of capillaries
in dermisin dermis
– during inflammation, infection, allergy or burnsduring inflammation, infection, allergy or burns

30. 3030
Accessory Structures of Accessory Structures of
SkinSkin
Epidermal derivativesEpidermal derivatives
Cells sink inward during Cells sink inward during
development to form:development to form:
–hairhair
–oil glandsoil glands
–sweat glandssweat glands
–nailsnails

31. 3131
Structure of HairStructure of Hair
 Shaft -- visibleShaft -- visible
–medulla, cortex & medulla, cortex &
cuticlecuticle
–CS round in straight CS round in straight
hairhair
–CS oval in wavy hairCS oval in wavy hair
 Root -- below the Root -- below the
surfacesurface
Follicle surrounds rootFollicle surrounds root
–external root sheathexternal root sheath
–internal root sheathinternal root sheath
–base of follicle is base of follicle is
bulbbulb
blood vesselsblood vessels
germinal cell layergerminal cell layer

32. 3232
Hair Related StructuresHair Related Structures

AArrector pilirrector pili
–smooth muscle in smooth muscle in
dermis contracts dermis contracts
with cold or fear.with cold or fear.
–forms goosebumps forms goosebumps
as hair is pulled as hair is pulled
verticallyvertically
Hair root plexusHair root plexus
–detect hair detect hair
movementmovement

33. 3333
Hair GrowthHair Growth
Growth cycle = growth stage & resting stageGrowth cycle = growth stage & resting stage
Growth stage Growth stage
– lasts for 2 to 6 yearslasts for 2 to 6 years
– matrix cells at base of hair root producing lengthmatrix cells at base of hair root producing length
 Resting stageResting stage
– lasts for 3 monthslasts for 3 months
–matrix cells inactive & follicle atrophiesmatrix cells inactive & follicle atrophies
Old hair falls out as growth stage begins againOld hair falls out as growth stage begins again
–normal hair loss is 70 to 100 hairs per daynormal hair loss is 70 to 100 hairs per day

34. 3434
Hair ColorHair Color
Result of melanin produced in melanocytes Result of melanin produced in melanocytes
in hair bulbin hair bulb
Dark hair contains true melaninDark hair contains true melanin
Blond and red hair contain melanin with iron Blond and red hair contain melanin with iron
and sulfur addedand sulfur added
Graying hair is result of decline in melanin Graying hair is result of decline in melanin
productionproduction
White hair has air bubbles in the medullary White hair has air bubbles in the medullary
shaftshaft

35. 3535
Functions ofFunctions of HairHair

PPrevents heat lossrevents heat loss
Decreases sunburnDecreases sunburn
Eyelashes help Eyelashes help
protect eyesprotect eyes
Touch receptors (hair Touch receptors (hair
root plexus) senses root plexus) senses
light touchlight touch

36. 3636
Glands of the SkinGlands of the Skin
Specialized exocrine glands found in Specialized exocrine glands found in
dermisdermis
Sebaceous (oil) glandsSebaceous (oil) glands
Sudiferous (sweat) glandsSudiferous (sweat) glands
Ceruminous (wax) glandsCeruminous (wax) glands
Mammary (milk) glandsMammary (milk) glands

37. 3737
Sebaceous (oil) glandsSebaceous (oil) glands
Secretory portion in the dermisSecretory portion in the dermis
Most open onto hair shafts Most open onto hair shafts
SebumSebum
–combination of cholesterol, proteins, fats & saltscombination of cholesterol, proteins, fats & salts
–keeps hair and skin soft & pliablekeeps hair and skin soft & pliable
–inhibits growth of bacteria & fungi(ringworm)inhibits growth of bacteria & fungi(ringworm)
AcneAcne
–bacterial inflammation of glandsbacterial inflammation of glands
–secretions stimulated by hormones at pubertysecretions stimulated by hormones at puberty

38. 3838
Sudoriferous (sweat) Sudoriferous (sweat)
glandsglands
 Eccrine (sweat) glandsEccrine (sweat) glands
–most areas of skinmost areas of skin
–secretory portion in dermis with duct to surfacesecretory portion in dermis with duct to surface
–regulate body temperature with perspirationregulate body temperature with perspiration
 Apocrine (sweat) glandsApocrine (sweat) glands
–armpit and pubic regionarmpit and pubic region
–secretory portion in dermis with duct that opens onto secretory portion in dermis with duct that opens onto
hair folliclehair follicle
–secretions more viscous secretions more viscous

39. 3939
Ceruminous glandsCeruminous glands
Modified sweat glands produce waxy Modified sweat glands produce waxy
secretion in ear canalsecretion in ear canal
Cerumin contains secretions of oil and Cerumin contains secretions of oil and
wax glandswax glands
Helps form barrier for entrance of foreign Helps form barrier for entrance of foreign
bodiesbodies
Impacted cerumen may reduce hearingImpacted cerumen may reduce hearing

40. 4040
NailsNails
Tightly packed, keratinized cellsTightly packed, keratinized cells
Nail body is pink due to underlying Nail body is pink due to underlying
capillariescapillaries
Lunula appears white due to thickened Lunula appears white due to thickened
stratum basale in that areastratum basale in that area
Cuticle (eponychium) is stratum corneumCuticle (eponychium) is stratum corneum
Nail matrix deep to the nail root is the region Nail matrix deep to the nail root is the region
from which the nail growth occursfrom which the nail growth occurs
Growth is 1mm per week--faster in summer Growth is 1mm per week--faster in summer
& on most-used hand& on most-used hand

41. 4141
Structure of NailsStructure of Nails
Tightly packed keratinized Tightly packed keratinized
cellscells
Nail bodyNail body
–visible portion pink due to visible portion pink due to
underlying capillariesunderlying capillaries
–free edge appears whitefree edge appears white
Nail rootNail root
–buried under skin layersburied under skin layers
–lunula is white due to lunula is white due to
thickened stratum basalethickened stratum basale
Eponychium (cuticle)Eponychium (cuticle)
–stratum corneum layerstratum corneum layer

42. 4242
Nail GrowthNail Growth
Nail matrix below nail root produces growthNail matrix below nail root produces growth
Cells transformed into tightly packed keratinized Cells transformed into tightly packed keratinized
cellscells
1 mm per week1 mm per week

43. 4343
Types of SkinTypes of Skin
Thin skinThin skin
–covers most of bodycovers most of body
–thin epidermis (.1 to .15 mm.) that lacks stratum thin epidermis (.1 to .15 mm.) that lacks stratum
lucidumlucidum
–lacks epidermal ridges, has fewer sweat glands lacks epidermal ridges, has fewer sweat glands
and sensory receptorsand sensory receptors
Thick skinThick skin
–only on palms and solesonly on palms and soles
–thick epidermis (.6 to 4.5 mm.) with distinct thick epidermis (.6 to 4.5 mm.) with distinct
stratum lucidum & thick stratum corneumstratum lucidum & thick stratum corneum
–lacks hair follicles and sebaceous glandslacks hair follicles and sebaceous glands

44. 4444
General Functions of the General Functions of the
SkinSkin
Regulation of body temperatureRegulation of body temperature
Protection as physical barrierProtection as physical barrier
Sensory receptors Sensory receptors
Excretion and absorptionExcretion and absorption
Synthesis of vitaminSynthesis of vitamin

45. 4545
Thermoregulation Thermoregulation
Releasing of sweat onto the skinReleasing of sweat onto the skin
–perspiration & its evaporation lowers body temperatureperspiration & its evaporation lowers body temperature
Adjusting flow of blood to the body surfaceAdjusting flow of blood to the body surface
–in moderate exercise, more blood brought to surface in moderate exercise, more blood brought to surface
helps lower temperaturehelps lower temperature
–with extreme exercise, blood is shunted to muscles and with extreme exercise, blood is shunted to muscles and
body temperature risesbody temperature rises
Shivering and constriction of surface vesselsShivering and constriction of surface vessels
–raise internal body temperature as neededraise internal body temperature as needed

46. 4646
ProtectionProtection
Physical, chemical and biological barrierPhysical, chemical and biological barrier
–tight cell junctions prevent bacterial invasiontight cell junctions prevent bacterial invasion
–lipids released retard evaporationlipids released retard evaporation
–pigment protects somewhat against UV lightpigment protects somewhat against UV light
–langerhans cells alert immune system langerhans cells alert immune system

47. 4747
Cutaneous SensationsCutaneous Sensations
Touch, temperature, pressure, vibration, Touch, temperature, pressure, vibration,
tickling and some pain sensations arise tickling and some pain sensations arise
from the skin.from the skin.

48. 4848
Excretion and AbsorptionExcretion and Absorption
Only a minor role is played by the skinOnly a minor role is played by the skin
400 mL of water evaporates from it daily400 mL of water evaporates from it daily
Small amounts salt, CO2, ammonia and urea Small amounts salt, CO2, ammonia and urea
are excretedare excreted
Lipid soluble substances can be absorbed Lipid soluble substances can be absorbed
through the skinthrough the skin
–vitamins A, D, E and K, Oxygen and CO2vitamins A, D, E and K, Oxygen and CO2
–acetone and dry-cleaning fluid, lead, mercury, acetone and dry-cleaning fluid, lead, mercury,
arsenic, poisons in poison ivy and oakarsenic, poisons in poison ivy and oak

49. 4949
Transdermal Drug AdministrationTransdermal Drug Administration
Method by which drugs in a patch enter the Method by which drugs in a patch enter the
bodybody
Drug absorption most rapid in areas where Drug absorption most rapid in areas where
skin is thin (scrotum, face and scalp)skin is thin (scrotum, face and scalp)
ExamplesExamples
–nitroglycerin (prevention of chest pain from nitroglycerin (prevention of chest pain from
coronary artery disease)coronary artery disease)
–scopolamine ( motion sickness)scopolamine ( motion sickness)
–estradiol (estrogen replacement therapy)estradiol (estrogen replacement therapy)
–nicotine (stop smoking alternative)nicotine (stop smoking alternative)

50. 5050
Synthesis of Vitamin DSynthesis of Vitamin D
Sunlight activates a precursor to vitamin DSunlight activates a precursor to vitamin D
Enzymes in the liver and kidneys Enzymes in the liver and kidneys
transform that molecule into calcitriol transform that molecule into calcitriol
(most active form of vitamin D)(most active form of vitamin D)
Necessary vitamin for absorption of Necessary vitamin for absorption of
calcium from food in the gastrointestinal calcium from food in the gastrointestinal
tracttract

51. 5151
Epidermal Wound HealingEpidermal Wound Healing
Abrasion or minor burnAbrasion or minor burn
Basal cells migrate across the woundBasal cells migrate across the wound
Contact inhibition with other cells stops migrationContact inhibition with other cells stops migration
Epidermal growth factor stimulates cell division Epidermal growth factor stimulates cell division
Full thickness of epidermis results from further cell Full thickness of epidermis results from further cell
divisiondivision

52. 5252
Deep Wound HealingDeep Wound Healing
If an injury reaches dermis, healing occurs in 4 phasesIf an injury reaches dermis, healing occurs in 4 phases
–inflammatory phase has clot unite wound edges and WBCs inflammatory phase has clot unite wound edges and WBCs
arrive from dilated and more permeable blood vesselsarrive from dilated and more permeable blood vessels
–migratory phase begins the regrowth of epithelial cells and migratory phase begins the regrowth of epithelial cells and
the formation of scar tissue by the fibroblaststhe formation of scar tissue by the fibroblasts
–proliferative phase is a completion of tissue formationproliferative phase is a completion of tissue formation
–maturation phase sees the scab fall offmaturation phase sees the scab fall off
Scar formationScar formation
–hypertrophic scar remains within the boundaries of the hypertrophic scar remains within the boundaries of the
original woundoriginal wound
–keloid scar extends into previously normal tissuekeloid scar extends into previously normal tissue
collagen fibers are very dense and fewer blood vessels are present collagen fibers are very dense and fewer blood vessels are present
so the tissue is lighter in colorso the tissue is lighter in color

53. 5353
Phases of Deep Wound HealingPhases of Deep Wound Healing
Which phases have been left out of this illustration?

54. 5454
Age Related Structural ChangesAge Related Structural Changes
Collagen fibers decrease in number & stiffen Collagen fibers decrease in number & stiffen
Elastic fibers become less elasticElastic fibers become less elastic
Fibroblasts decrease in numberFibroblasts decrease in number
Langerhans cells and macrophages decrease Langerhans cells and macrophages decrease
in number and become less-efficient in number and become less-efficient
phagocytesphagocytes
Oil glands shrink and the skin becomes dryOil glands shrink and the skin becomes dry
Walls of blood vessels in dermis thicken so Walls of blood vessels in dermis thicken so
decreased nutrient availability leads to thinner decreased nutrient availability leads to thinner
skin as subcutaneous fat is lostskin as subcutaneous fat is lost

55. 5555
PhotodamagePhotodamage
Ultraviolet light (UVA and UVB) both Ultraviolet light (UVA and UVB) both
damage the skindamage the skin
Acute overexposure causes sunburnAcute overexposure causes sunburn
DNA damage in epidermal cells can lead DNA damage in epidermal cells can lead
to skin cancerto skin cancer
UVA produces oxygen free radicals that UVA produces oxygen free radicals that
damage collagen and elastic fibers and damage collagen and elastic fibers and
lead to wrinkling of the skinlead to wrinkling of the skin

56. 5656
Skin CancerSkin Cancer
1 million cases diagnosed per year1 million cases diagnosed per year
3 common forms of skin cancer3 common forms of skin cancer
–basal cell carcinoma (rarely metastasize)basal cell carcinoma (rarely metastasize)
–squamous cell carcinoma (may metastasize)squamous cell carcinoma (may metastasize)
–malignant melanomas (metastasize rapidly) malignant melanomas (metastasize rapidly)
most common cancer in young womenmost common cancer in young women
arise from melanocytes ----life threateningarise from melanocytes ----life threatening
key to treatment is early detection watch for changes in key to treatment is early detection watch for changes in
symmetry, border, color and sizesymmetry, border, color and size
risks factors include-- skin color, sun exposure, family history, risks factors include-- skin color, sun exposure, family history,
age and immunological statusage and immunological status

57. Tumors of the skinTumors of the skin
Benign, e.g. wartsBenign, e.g. warts
Cancer – associated with UV exposure (also Cancer – associated with UV exposure (also
skin aging)skin aging)
–Aktinic keratosis - premalignantAktinic keratosis - premalignant
–Basal cell - cells of stratum basaleBasal cell - cells of stratum basale
–Squamous cell - keratinocytesSquamous cell - keratinocytes
–Melanoma – melanocytes: most dangerous; Melanoma – melanocytes: most dangerous;
recognition:recognition:
A - A - AAsymmetrysymmetry
B - B - BBorder irregularityorder irregularity
C - C - CColorsolors
D - D - DDiameter larger than 6 mmiameter larger than 6 mm

58. Basal cell carcinoma
Sqaumous cell carcinoma
Melanoma
Skin Cancer

59. 5959
BurnsBurns
Destruction of proteins of the skinDestruction of proteins of the skin
–chemicals, electricity, heatchemicals, electricity, heat
Problems that resultProblems that result
–shock due to water, plasma and plasma protein shock due to water, plasma and plasma protein
lossloss
–circulatory & kidney problems from loss of circulatory & kidney problems from loss of
plasmaplasma
–bacterial infectionbacterial infection

60. 6060
Types of BurnsTypes of Burns
First-degreeFirst-degree
–only epidermis (sunburn)only epidermis (sunburn)
Second-degree burn Second-degree burn
–destroys entire epidermis & part of dermis destroys entire epidermis & part of dermis
–fluid-filled blisters separate epidermis & dermisfluid-filled blisters separate epidermis & dermis
–epidermal derivatives are not damagedepidermal derivatives are not damaged
–heals without grafting in 3 to 4 weeks & may scarheals without grafting in 3 to 4 weeks & may scar
Third-degree or full-thicknessThird-degree or full-thickness
–destroy epidermis, dermis & epidermal derivativesdestroy epidermis, dermis & epidermal derivatives
–damaged area is numb due to loss of sensory damaged area is numb due to loss of sensory
nervesnerves

61. 6161

62. 6262
Pressure SoresPressure Sores
Decubitus ulcersDecubitus ulcers
Caused by constant deficiency of blood Caused by constant deficiency of blood
flow to tissueflow to tissue
Areas affected is skin over bony Areas affected is skin over bony
prominence in bedridden patientsprominence in bedridden patients
Preventable with proper carePreventable with proper care