the skin function –protective covering bacterial infection physical trauma –receptors touch,...
TRANSCRIPT
THE SKIN• Function
– Protective covering• Bacterial infection• Physical trauma
– Receptors• Touch, pressure, pain, heat and cold
– Vitamin D production• UV light
– Regulation of body temperature• Dilation or constriction of blood vessels• Sweat glands
Epidermis
Epidermis
DermisDermis
Hypodermis (Subcutaneous Layer)
Hypodermis (Subcutaneous Layer)
SKIN REGIONS
SKIN REGIONS
• Epidermis– Protective outer
epithelial layer– Avascular
DermisTough,
fibrous connective tissue layer
Largest region of the skin
Vascular
DermisTough,
fibrous connective tissue layer
Largest region of the skin
Vascular
SKIN REGIONS
HypodermisRegion just
deep to the dermis
Adipose and areolar C.T.
Anchors the skin
HypodermisRegion just
deep to the dermis
Adipose and areolar C.T.
Anchors the skin
SKIN REGIONS
Stratum corneumStratum corneum
Stratum lucidumStratum lucidumStratum granulosum
Stratum granulosum
Stratum spinosumStratum
spinosum
Stratum basale
Stratum basale
LAYERS of the EPIDERMIS
THE EPIDERMIS• Definition
– Keratinized, stratified squamous E.T.
• Layers– Five layers in thick skin
– Four in all other skin
THE EPIDERMIS
• Cells– Keratinocytes
• Most numerous cell type• Produce the protein keratinkeratin for waterproofing and
protection• Replaced every 25 to 45 days
EPIDERMAL LAYERS• Stratum Basale
– Deepest layer– Attached to dermis– Single layer of cuboidal
keratinocytes– Mitotic layer– Contains melanocytesmelanocytes
• Produce the pigment melanin
– Contains Merkel’s discs =Merkel’s discs =• Sensory nerve endings
• Pressure
melanocytes
EPIDERMAL LAYERS: Stratum Basale
EPIDERMAL LAYERSEPIDERMAL LAYERS Stratum Spinosum
Several layers of keratinocytes with a “spiny” appearance
Scattered melanin granules
Langerhan cellsLangerhan cells = macrophages
Stratum SpinosumSeveral layers of
keratinocytes with a “spiny” appearance
Scattered melanin granules
Langerhan cellsLangerhan cells = macrophages
EPIDERMAL LAYERS: Stratum Spinosum
EPIDERMAL LAYERSEPIDERMAL LAYERS Stratum
GranulosumThin region of
dark-staining cellsFlat cells with
keratohyalinekeratohyaline granules
Cells above are dead
Stratum GranulosumThin region of
dark-staining cellsFlat cells with
keratohyalinekeratohyaline granules
Cells above are dead
EPIDERMAL LAYERS:Stratum Granulosum
EPIDERMAL LAYERSEPIDERMAL LAYERS Stratum Lucidum
Only present in thick skin
Thin, translucent layer of dead keratinocytes
Stratum LucidumOnly present in
thick skinThin, translucent
layer of dead keratinocytes
EPIDERMAL LAYERS:Stratum Lucidum
EPIDERMAL LAYERSEPIDERMAL LAYERS Stratum Corneum
Outer, loose layer of dead, flaky cells
Protects skin from:Abrasion or
penetration
Stratum CorneumOuter, loose layer
of dead, flaky cellsProtects skin
from:Abrasion or
penetration
EPIDERMAL LAYERS: Stratum Corneum
THE DERMISTHE DERMIS
DefinitionA thick, flexible C.T. layerRich in nerve fibersVery vascular
LayersPapillary layerReticular layer
DefinitionA thick, flexible C.T. layerRich in nerve fibersVery vascular
LayersPapillary layerReticular layer
THE DERMIS
Papillary LayerLoosely wovenHighly vascularContains:
Dermal papillaeMeissner’s
corpuscles• Detect touch
Free nerve endings• Detect pain
Larger dermal folds form ridges = fingerprintsOn palms of hands
and soles of feet
Papillary LayerLoosely wovenHighly vascularContains:
Dermal papillaeMeissner’s
corpuscles• Detect touch
Free nerve endings• Detect pain
Larger dermal folds form ridges = fingerprintsOn palms of hands
and soles of feet
dermal papillae
Meissner’s corpuscle
LAYERS of the DERMIS
dermal papilla
epidermal peg
STRUCTURES of the DERMIS
Meissner’s CorpuscleMeissner’s Corpuscle
STRUCTURES of the DERMIS
Reticular LayerMakes up 80% of
the dermisDense, irregular
C.T. rich in collagenContains:
Hair folliclesSebaceous glandsBlood vessels and
nerves Pacinian corpusclesPacinian corpuscles
in deep regions• Detect crude
touch; deep pressure
Reticular LayerMakes up 80% of
the dermisDense, irregular
C.T. rich in collagenContains:
Hair folliclesSebaceous glandsBlood vessels and
nerves Pacinian corpusclesPacinian corpuscles
in deep regions• Detect crude
touch; deep pressure
Pacinian corpuscle
LAYERS of the DERMIS
Pacinian CorpusclePacinian Corpuscle
STRUCTURES of the DERMIS
Three Pigments Determine Skin ColorMelanin
Brown to black pigmentPrevents UV damage
CaroteneYellowish, orange pigmentNoticeable in the palms and soles
HemoglobinRed pigment when oxygenatedGives the skin a bluish or gray appearance when poorly oxygenated (cyanosis)
Three Pigments Determine Skin ColorMelanin
Brown to black pigmentPrevents UV damage
CaroteneYellowish, orange pigmentNoticeable in the palms and soles
HemoglobinRed pigment when oxygenatedGives the skin a bluish or gray appearance when poorly oxygenated (cyanosis)
SKIN COLOR
DefinitionKeratinized cells produced by hair
follicles
Hair StructurePapillaPapilla
At the hair baseSupplies the cells with nutrients
Arrector piliArrector piliSmooth musclesPull hair upright
DefinitionKeratinized cells produced by hair
follicles
Hair StructurePapillaPapilla
At the hair baseSupplies the cells with nutrients
Arrector piliArrector piliSmooth musclesPull hair upright
APPENDAGES of the SKIN: Hair and Hair Follicles
papilla
epidermal tissue
Hair and Hair Follicles
Arrector Pili Muscle
Arrector Pili Muscle
Hair and Hair Follicles
Types of HairVellus HairVellus Hair
Soft body hair of children and adult females
Terminal HairTerminal HairCoarse, longer growing hairFound:
•Eyebrows, head, armpits, pubic regions of adults
• Face, chest, arms and legs of adult males
Types of HairVellus HairVellus Hair
Soft body hair of children and adult females
Terminal HairTerminal HairCoarse, longer growing hairFound:
•Eyebrows, head, armpits, pubic regions of adults
• Face, chest, arms and legs of adult males
APPENDAGES of the SKIN: Hair and Hair Follicles
DefinitionEpidermal
modificationsProtects the dorsum of the fingers and toes
Contain keratinkeratin
DefinitionEpidermal
modificationsProtects the dorsum of the fingers and toes
Contain keratinkeratin
APPENDAGES of the SKIN:Nails
Two Types:Eccrine Sweat Eccrine Sweat
GlandsGlandsOpen to skin surface
Regulation of body temperature
Two Types:Eccrine Sweat Eccrine Sweat
GlandsGlandsOpen to skin surface
Regulation of body temperatureMerocrine
sweat gland
APPENDAGES of the SKIN: Sudoriferous (Sweat) Glands
Apocrine Sweat Apocrine Sweat GlandsGlandsOpen into hair follicles in anal, groin and axillary region
Active at pubertyNot important in thermoregulation
Active during stress
Apocrine Sweat Apocrine Sweat GlandsGlandsOpen into hair follicles in anal, groin and axillary region
Active at pubertyNot important in thermoregulation
Active during stress
Apocrine sweat gland
APPENDAGES of the SKIN: Sudoriferous (Sweat) Glands
Sudoriferous (Sweat) Glands
DefinitionModified sweat
glandsWithin breastsProduce milk following childbirth
DefinitionModified sweat
glandsWithin breastsProduce milk following childbirth
mammary glands
APPENDAGES of the SKIN: Mammary Glands
DefinitionSimple alveolar
glands found all over the body except on the palms and solesNear hair follicles
Secretes sebumsebum
DefinitionSimple alveolar
glands found all over the body except on the palms and solesNear hair follicles
Secretes sebumsebum
Sebaceous gland
APPENDAGES of the SKIN: Sebaceous (Oil) Glands
Sebaceous (Oil) Glands
HyperthermiaHyperthermiaAn abnormally high body
temperatureCan result in:
•Heat exhaustion (headache, vomiting, and tiredness)
•Heat stroke (dizziness, confusion, delusions)
•Increased fluid intake and possible medical care are needed in both cases
Fever•Hyperthermia brought on by illness
•Body’s attempt to fight off infection
HyperthermiaHyperthermiaAn abnormally high body
temperatureCan result in:
•Heat exhaustion (headache, vomiting, and tiredness)
•Heat stroke (dizziness, confusion, delusions)
•Increased fluid intake and possible medical care are needed in both cases
Fever•Hyperthermia brought on by illness
•Body’s attempt to fight off infection
SKIN DISORDERS
HypothermiaHypothermiaAn abnormally low body
temperatureResults in:
•Shivering, incoherent speech and lack of coordination
•Body functions slow and death occurs when metabolism stops completely
•Person must be warmed immediately
HypothermiaHypothermiaAn abnormally low body
temperatureResults in:
•Shivering, incoherent speech and lack of coordination
•Body functions slow and death occurs when metabolism stops completely
•Person must be warmed immediately
SKIN DISORDERS
Skin CancerSkin CancerSquamous cell carcinoma and
basal cell carcinomaMost commonLikely caused by sun exposureSurgical removal is the standard treatment
MelanomaArises from melanocytesCan metastasize
Skin CancerSkin CancerSquamous cell carcinoma and
basal cell carcinomaMost commonLikely caused by sun exposureSurgical removal is the standard treatment
MelanomaArises from melanocytesCan metastasize
SKIN DISORDERS
Basal Cell Carcinom
a
Basal Cell Carcinom
a
Squamous Cell
Carcinoma
Squamous Cell
Carcinoma
Malignant MelanomaMalignant Melanoma
SKIN CANCER
BurnsBurnsFactors affecting burn severity
Depth of burnExtent of area burned
Classification of burns1st degree burns
•Epidermis is burned: redness and pain
•Damaged skin peels off
BurnsBurnsFactors affecting burn severity
Depth of burnExtent of area burned
Classification of burns1st degree burns
•Epidermis is burned: redness and pain
•Damaged skin peels off
SKIN DISORDERS
BurnsBurnsClassification of burns
2nd degree burns•Extends through epidermis and part of the dermis
•Results in redness, pain and blisters•May result in scarring
BurnsBurnsClassification of burns
2nd degree burns•Extends through epidermis and part of the dermis
•Results in redness, pain and blisters•May result in scarring
SKIN DISORDERS
BurnsBurnsClassification of burns
3rd degree burns•Entire thickness of skin is burnt•Blood vessels, sweat glands, and other skin accessories are also burnt
•Fluid and heat loss and bacterial infection
•Skin grafting required•Survival chances are not good if large area
BurnsBurnsClassification of burns
3rd degree burns•Entire thickness of skin is burnt•Blood vessels, sweat glands, and other skin accessories are also burnt
•Fluid and heat loss and bacterial infection
•Skin grafting required•Survival chances are not good if large area
SKIN DISORDERS
2nd Degree Burn
2nd Degree Burn
3rd Degree Burn
3rd Degree Burn
1st Degree Burn
1st Degree Burn
BURNS
