the integumentary system. what is the integumentary system? an organ system an organ system several...
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The Integumentary SystemThe Integumentary System
What is the integumentary What is the integumentary system?system?
An organ systemAn organ systemSeveral tissue types functioning togetherSeveral tissue types functioning together
Largest organ of bodyLargest organ of bodyManyMany functions: functions:
Protection, insulation, cushion, prevent water loss, regulate heat loss, Protection, insulation, cushion, prevent water loss, regulate heat loss, excretion through pores, vitamin D synthesis, sensory inputexcretion through pores, vitamin D synthesis, sensory input
2 Main Regions2 Main Regions
Epidermis
Dermis
EPIDERMIS: 4-5 layersEPIDERMIS: 4-5 layersStratum corneumStratum corneumStratum lucidumStratum lucidumStratum granulosumStratum granulosumStratum spinosumStratum spinosumStratum basaleStratum basale
SUPERFICIALSUPERFICIAL
DEEPDEEP
© 2014 Pearson Education, Inc.
Figure 7.2 The main structural features in epidermis of thin skin.
Dermis
Desmosomes
Melaningranule
Melanocyte
Tactile(Merkel)cell
Sensorynerveending
Dermis
Keratinocytes Dendritic cell
Stratum corneumMost superficial layer; 20–30 layersof dead cells, essentially flatmembranous sacs filled with keratin.Glycolipids in extracellular space.
Stratum granulosumOne to five layers of flattened cells,organelles deteriorating; cytoplasmfull of lamellar granules (releaselipids) and keratohyaline granules.
Stratum spinosumSeveral layers of keratinocytesjoined by desmosomes. Cellscontain thick bundles ofintermediate filaments made ofpre-keratin.
Stratum basaleDeepest epidermal layer; one rowof actively mitotic stem cells;some newly formed cells becomepart of the more superficiallayers.
TOP: Stratum corneumTOP: Stratum corneumStratum corneumMost superficial layer; 20–30 layers of dead cells, essentially flat membranous sacs filled with keratin.Glycolipids in extracellular space.
22ndnd (if present) Stratum (if present) Stratum lucidumlucidum
Thin, clear layerThin, clear layerFlattened dead cells, filled with keratin Flattened dead cells, filled with keratin OnlyOnly in “thick skin”: palms, soles in “thick skin”: palms, soles
Fig. 5-4
33rdrd (if thick skin) (if thick skin) Stratum Stratum granulosumgranulosum
Fig. 5-4
Stratum granulosumOne to five layers of flattened cells,organelles deteriorating; Cytoplasm full of lamellar granules (release lipids) and keratohyaline granules.
44thth Stratum spinosum Stratum spinosumStratum spinosumSeveral layers of keratinocytesjoined by desmosomes. Cells contain thick bundles ofintermediate filaments made ofpre-keratin.
KeratinocytesDendritic cell
55thth (bottom) (bottom) Stratum basaleStratum basale
Stratum basaleDeepest epidermal layer; one row of actively mitotic stem cells;some newly formed cells becomepart of the more superficiallayers.
DesmosomesMelaningranule
Melanocyte
Tactile(Merkel)cell
Sensorynerveending
Dermis
Epidermal cellsEpidermal cellsKeratinocytesKeratinocytes: most abundant, produce keratin: most abundant, produce keratinMelanocytesMelanocytes: produce melanin, shield nuclei from : produce melanin, shield nuclei from
UV, freckle = many in one spotUV, freckle = many in one spotLangerhansLangerhans cellscells: macrophages (immune system) : macrophages (immune system)
that help stimulate a defense; in s. spinosumthat help stimulate a defense; in s. spinosumMerkelMerkel cellscells: sensory touch receptors; in s. basale: sensory touch receptors; in s. basale
Papillary layer Papillary layer superficial, just below the epidermissuperficial, just below the epidermis
Reticular layer Reticular layer deep, below the papillary layerdeep, below the papillary layer
DERMIS: 2 layersDERMIS: 2 layers
© 2014 Pearson Education, Inc.
Figure 7.1 Skin structure.
Hair shaft
Papillarylayer
Reticularlayer
Dermal papillae
Subpapillaryplexus
Sweat pore
• Eccrine sweat gland• Arrector pili muscle• Sebaceous (oil) gland• Hair follicle• Hair root
Cutaneous plexus
Adipose tissue
Appendages of skin
Nervous structures
Epidermis
Dermis
Hypodermis(subcutaneous tissue;not part of skin)
• Sensory nerve fiber with free nerve endings
• Lamellar corpuscle• Hair follicle receptor (root hair plexus)
Dermal papillae (projections) extend from upper Dermal papillae (projections) extend from upper dermis into epidermal ridgesdermis into epidermal ridgesEpidermal ridges formed by stratum basale, at Epidermal ridges formed by stratum basale, at
junction of epidermis & dermis junction of epidermis & dermis FINGERPRINTS! FINGERPRINTS!Areolar tissueAreolar tissue
Papillary LayerPapillary Layer
Thicker layerThicker layerDense irregular connective tissueDense irregular connective tissueFibers Fibers Vascular, glandular (sweat/sebaceous)Vascular, glandular (sweat/sebaceous)Stretch marks: dermis is torn because stretched Stretch marks: dermis is torn because stretched
too far…then repairedtoo far…then repaired
Reticular LayerReticular Layer
Dermal CellsDermal CellsMeissner’s corpusclesMeissner’s corpuscles: light touch receptors in : light touch receptors in
dermis—PAPILLARY LAYERdermis—PAPILLARY LAYER
Pacinian (lamellar) corpusclesPacinian (lamellar) corpuscles: deep pressure : deep pressure receptors in dermis—RETICULAR LAYERreceptors in dermis—RETICULAR LAYER
HypodermisHypodermisDeep to the dermis (below it)Deep to the dermis (below it)Superficial fascia layerSuperficial fascia layerPrimarily adipose tissuePrimarily adipose tissueNOT a part of the “skin”NOT a part of the “skin”
Accessory Skin OrgansAccessory Skin OrgansHairHairNailsNailsCutaneous GlandsCutaneous Glands
Hair follicleHair follicleTubular Tubular
depression in depression in epidermis & epidermis & dermisdermis
Where a hair Where a hair developsdevelops
Follicle wall
Hair bulbHair bulb(root), (root),
within the within the hair hair follicle, follicle, the the enlarged enlarged base base
Hair bulb
Root sheathRoot sheathInner Inner
cylinder of cylinder of epidermis epidermis surrounding surrounding hair root in hair root in the folliclethe follicle
• Internal epithelial root sheath
• External epithelial root sheath
Arrector piliArrector piliSmooth muscle cellsSmooth muscle cellsConnect hair follicle to Connect hair follicle to
papillary layerpapillary layerMuscles contract Muscles contract
hair stands up, hair stands up, goosebumps b/c skin goosebumps b/c skin dimpleddimpled
Arrectorpili muscle
Hair shaftHair shaftVisible, dead Visible, dead
(keratinized) (keratinized) portion of the portion of the hairhair
Hair shaft
Figure 7.6 Photomicrographs of skin.
Hair follicle
Sloughing stratumcorneum cells
Hair shaft
Epidermis
Dermis
Epidermis
Dermis
• Stratum corneum
• Stratum lucidum
• Stratum granulosum
• Stratum spinosum
• Stratum basale
NAILSNAILSAre in the integumentary systemAre in the integumentary systemDon’t need to know the specifics FOR LABDon’t need to know the specifics FOR LAB
Cutaneous GlandsCutaneous GlandsSebaceous GlandsSebaceous Glands
Sweat GlandsSweat GlandsEccrineEccrineApocrineApocrine
Sebaceous GlandsSebaceous Glands““oil glands”oil glands”Associated with hair follicleAssociated with hair follicleSecrete sebum into hair follicle to keep hair from Secrete sebum into hair follicle to keep hair from
being brittle (holocrine gland)being brittle (holocrine gland)Sebaceousgland
Sweat GlandsSweat GlandsExocrine glands, all over body (pores)Exocrine glands, all over body (pores)2 types of fluid:2 types of fluid:
Eccrine glandsEccrine glands Forehead, back, palms, solesForehead, back, palms, soles Clear perspiration (water, salts, urea: exocytosis), controls body Clear perspiration (water, salts, urea: exocytosis), controls body
temperaturetemperature Merocrine glandsMerocrine glands
Apocrine glandsApocrine glands Much Much largerlarger Axillary, pubic, mammary (specialized, produces milk)Axillary, pubic, mammary (specialized, produces milk) ““cloudy” perspiration, odorouscloudy” perspiration, odorous Olfactory communication--pheromonesOlfactory communication--pheromones
Eccrinegland
Skin Model Key:
I. EpidermisII. DermisIII. Hypodermis (subcutaneous)1. Stratum corneum1a. Stratum lucidum2. Stratum germatativum2a. Stratum granulosum2b. Stratum spinosum2c. Stratum basale3. Papillae4. Touch (Meissner) corpuscle5. Adipose tissue6. Laminated (Pacinian) corpuscle7. Sweat (Eccrine) gland8. Hair (longitudinal section)
8a. Medulla8a. Medulla8b. Cortex8b. Cortex8c. Cuticle8c. Cuticle8d. Internal epithelial root sheath8d. Internal epithelial root sheath8e. External or outer epithelial root 8e. External or outer epithelial root sheathsheath8f. Glassy (hyaloid) membrane8f. Glassy (hyaloid) membrane8g. Fibrous connective tissue root 8g. Fibrous connective tissue root sheathsheath9. Hair (cross-section)9. Hair (cross-section)10. Hair shaft10. Hair shaft11. Root11. Root11a. Hair bulb11a. Hair bulb12. Hair papilla12. Hair papilla13. Sebaceous glands13. Sebaceous glands14. Arrector pili muscle14. Arrector pili muscle15. Sweat (apocrine) gland15. Sweat (apocrine) gland15a. Smooth muscle cells15a. Smooth muscle cells15b. Hyaline top15b. Hyaline top15c. Part of the pushed out cell body15c. Part of the pushed out cell body
Interactive website—quiz yourself!http://daphne.palomar.edu/ccarpenter/Models/skin_model_2.htm
Review Figure 7.1