Chapter 5: The Integumentary System. What are the structures and functions of the integumentary...
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Transcript of Chapter 5: The Integumentary System. What are the structures and functions of the integumentary...
Chapter 5: Chapter 5: The Integumentary The Integumentary
SystemSystem
What are the structures What are the structures and functions of the and functions of the
integumentary system?integumentary system?
Size of the IntegumentSize of the Integument
The The integumentintegument is the largest system of is the largest system of the body:the body: 16% of body weight16% of body weight 1.5 to 2 m1.5 to 2 m22 in area in area
Parts of the IntegumentParts of the Integument
The integument is made up of The integument is made up of
2 parts:2 parts:1.1. cutaneous membranecutaneous membrane (skin) (skin)
2.2. accessory structuresaccessory structures
Parts of the Parts of the Integumentary SystemIntegumentary System
Parts of the Parts of the Cutaneous MembraneCutaneous Membrane
Outer Outer epidermisepidermis:: superficial epithelium (epithelial tissues)superficial epithelium (epithelial tissues)
Inner Inner dermisdermis:: connective tissuesconnective tissues
Accessory StructuresAccessory Structures
Originate in the dermisOriginate in the dermis Extend through the epidermis to skin Extend through the epidermis to skin
surface:surface: hairhair nailsnails multicellular exocrine glandsmulticellular exocrine glands
ConnectionsConnections
Circulatory system:Circulatory system: blood vessels in the dermisblood vessels in the dermis
Nervous system:Nervous system: sensory receptors for pain, touch, and sensory receptors for pain, touch, and
temperaturetemperature
The Subcutaneous LayerThe Subcutaneous Layer
Subcutaneous layerSubcutaneous layer (superficial fascia or (superficial fascia or hypodermis)hypodermis): : loose connective tissueloose connective tissue below the dermis below the dermis location of hypodermic injectionslocation of hypodermic injections
Functions of SkinFunctions of Skin
ProtectsProtects underlying tissues and organs underlying tissues and organs ExcretesExcretes salts, water, and organic wastes salts, water, and organic wastes
(glands)(glands) MaintainsMaintains body temperature (insulation body temperature (insulation
and evaporation)and evaporation)
Functions of SkinFunctions of Skin
SynthesizesSynthesizes vitamin D vitamin D33
StoresStores lipids lipids DetectsDetects touch, pressure, pain, and touch, pressure, pain, and
temperaturetemperature
What are the main structures and functions of the epidermis?
Cells of the EpidermisCells of the Epidermis
KeratinocytesKeratinocytes:: contain large amounts of keratincontain large amounts of keratin the most abundant cells in the epidermisthe most abundant cells in the epidermis
EpidermisEpidermis
Avascular stratified squamous epitheliumAvascular stratified squamous epithelium Nutrients and oxygen diffuse from Nutrients and oxygen diffuse from
capillaries in the dermiscapillaries in the dermis
Thin SkinThin Skin
Covers most of the body Covers most of the body Has 4 layers of keratinocytesHas 4 layers of keratinocytes
Layer of skinLayer of skin
Stratum germinativumStratum germinativum Epidermal ridges Epidermal ridges
Page 156Page 156
Stratum spinosumStratum spinosum Spiny layersSpiny layers
P 156P 156
Stratum granulosumStratum granulosum Grainy layer Grainy layer
5 layers of skin only5 layers of skin only
Stratum lucidumStratum lucidum Only in palms and soles Only in palms and soles
p156p156
Stratum corneumStratum corneum DeadDead
• 15 – 30 cell layers15 – 30 cell layers• Water resistant – not waterproofWater resistant – not waterproof
Thick SkinThick Skin
Covers the palms of the hands and soles Covers the palms of the hands and soles of the feetof the feet
Has 5 layers of keratinocytesHas 5 layers of keratinocytes
Skin Life CycleSkin Life Cycle
It takes 15–30 days for a cell to move It takes 15–30 days for a cell to move from from stratum germinosumstratum germinosum to to stratum stratum corneumcorneum
What causes different skin colors?
Skin ColorSkin Color
Skin color depends on:Skin color depends on: the pigments the pigments carotenecarotene and and melaninmelanin blood circulation (red cells)blood circulation (red cells)
CaroteneCarotene
Orange-yellow pigmentOrange-yellow pigment Found in orange vegetablesFound in orange vegetables Accumulates in epidermal cells and fatty Accumulates in epidermal cells and fatty
tissues of the dermistissues of the dermis Can be converted to vitamin ACan be converted to vitamin A
MelaninMelanin
Yellow-brown or black pigmentYellow-brown or black pigment Produced by Produced by melanocytesmelanocytes in stratum in stratum
germinativumgerminativum Stored in transport vesicles Stored in transport vesicles
((melanosomesmelanosomes)) Transferred to keratinocytesTransferred to keratinocytes
Function of MelanocytesFunction of Melanocytes
Melanin protects skin from sun damageMelanin protects skin from sun damage Ultraviolet (UV) radiationUltraviolet (UV) radiation::
causes DNA mutations and burns which lead causes DNA mutations and burns which lead to cancer and wrinklesto cancer and wrinkles
MelanocytesMelanocytes
Skin color depends on melanin production, Skin color depends on melanin production, not number of melanocytesnot number of melanocytes
Capillaries and Skin ColorCapillaries and Skin Color
Oxygenated red blood contributes to skin Oxygenated red blood contributes to skin color: color: blood vessels dilate from heat, skin reddensblood vessels dilate from heat, skin reddens blood flow decreases, skin palesblood flow decreases, skin pales
CyanosisCyanosis
Bluish skin tintBluish skin tint Caused by severe reduction in blood flow Caused by severe reduction in blood flow
or oxygenationor oxygenation
Illness and Skin ColorIllness and Skin Color
JaundiceJaundice:: buildup of bile produced by liverbuildup of bile produced by liver yellow coloryellow color
Addison’s diseaseAddison’s disease:: and other diseases of and other diseases of pituitary glandpituitary gland skin darkeningskin darkening
What are the structures and What are the structures and functions of the dermis?functions of the dermis?
The The DermisDermis
Is located between epidermis and Is located between epidermis and subcutaneous layersubcutaneous layer
Anchors epidermal accessory structures Anchors epidermal accessory structures (hair follicles, sweat glands) (hair follicles, sweat glands)
Characteristics of DermisCharacteristics of Dermis
Strong, due to collagen fibersStrong, due to collagen fibers Elastic, due to elastic fibersElastic, due to elastic fibers Flexible (Flexible (skin turgorskin turgor))
Skin DamageSkin Damage
Sagging and wrinkles (reduced skin Sagging and wrinkles (reduced skin elasticity) are caused by:elasticity) are caused by: dehydrationdehydration ageage hormonal changeshormonal changes UV exposure UV exposure
Lines of CleavageLines of Cleavage
Collagen and elastic fibers in the dermis: Collagen and elastic fibers in the dermis: are arranged in parallel bundlesare arranged in parallel bundles resist force in a specific directionresist force in a specific direction
Clinical ImportanceClinical Importance
Lines of cleavageLines of cleavage establish important establish important patterns:patterns: a parallel cut remains shut, heals wella parallel cut remains shut, heals well a cut across (right angle) pulls open and scars a cut across (right angle) pulls open and scars
Lines of CleavageLines of Cleavage
Dermal CirculationDermal Circulation
What are the structures What are the structures and functions of the and functions of the subcutaneous layer?subcutaneous layer?
The HypodermisThe Hypodermis
The The subcutaneous layersubcutaneous layer or or hypodermishypodermis: : lies below the integumentlies below the integument stabilizes the skinstabilizes the skin allows separate movementallows separate movement
What are the skin glands What are the skin glands and secretions?and secretions?
Exocrine GlandsExocrine Glands
Sebaceous glandsSebaceous glands (oil glands): (oil glands): holocrine glandsholocrine glands secrete secrete sebumsebum
Sweat glandsSweat glands:: merocrine glandsmerocrine glands watery secretionswatery secretions
Types of Sebaceous GlandsTypes of Sebaceous Glands
Simple branched alveolar glandsSimple branched alveolar glands:: associated with hair follicles associated with hair follicles
Sebaceous folliclesSebaceous follicles:: discharge directly onto skin surfacedischarge directly onto skin surface
Sebaceous GlandsSebaceous Glands
SebumSebum
Contains lipids and other ingredientsContains lipids and other ingredients Lubricates and protects the epidermisLubricates and protects the epidermis Inhibits bacteriaInhibits bacteria
What are the functions of sweat glands?
Types of Sweat GlandsTypes of Sweat Glands
ApocrineApocrine:: found in armpits, around nipples, and groinfound in armpits, around nipples, and groin
MerocrineMerocrine:: widely distributed on body surfacewidely distributed on body surface especially on palms and solesespecially on palms and soles
Apocrine Sweat GlandsApocrine Sweat Glands
Merocrine secretions, not apocrineMerocrine secretions, not apocrine Associated with hair folliclesAssociated with hair follicles Produce sticky, cloudy secretions Produce sticky, cloudy secretions Break down and cause odorsBreak down and cause odors
Merocrine Sweat GlandsMerocrine Sweat Glands
Also called Also called eccrine glandseccrine glands:: coiled, tubular glandscoiled, tubular glands discharge directly onto skin surfacedischarge directly onto skin surface sensible perspirationsensible perspiration water, salts, and organic compoundswater, salts, and organic compounds
Functions of Merocrine SweatFunctions of Merocrine Sweat
Cools skinCools skin Excretes water and electrolytesExcretes water and electrolytes Flushes microorganisms and harmful Flushes microorganisms and harmful
chemicals from skinchemicals from skin