© 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body...
-
Upload
april-johnson -
Category
Documents
-
view
214 -
download
1
Transcript of © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body...
![Page 1: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/1.jpg)
© 2012 Pearson Education, Inc.
The Integument o Is the largest system of the body
• 16% of body weight
• 1.5 to 2 m2 in area
• The integument is made up of two parts
1. Cutaneous membrane (skin)
2. Accessory structures
![Page 2: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/2.jpg)
© 2012 Pearson Education, Inc.
Two Components of the Cutaneous Membrane
1. Outer epidermis
• Superficial epithelium (epithelial tissues)
2. Inner dermis
• Connective tissues
![Page 3: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/3.jpg)
© 2012 Pearson Education, Inc.
Accessory Structures
o Originate in the dermis
o Extend through the epidermis to skin surface
• Hair
• Nails
• Multicellular exocrine glands
![Page 4: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/4.jpg)
© 2012 Pearson Education, Inc.
Connections
o Cardiovascular system
• Blood vessels in the dermis
o Nervous system
• Sensory receptors for pain, touch, and temperature
![Page 5: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/5.jpg)
© 2012 Pearson Education, Inc.
Hypodermis (Superficial Fascia or Subcutaneous
Layer)
o Loose connective tissue
o Below the dermis
o Location of hypodermic injections
![Page 6: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/6.jpg)
Cutaneous MembraneAccessory Structures
Epidermis
Dermis
Papillary layer
Reticular layer
Hypodermis
Hair shaft
Pore of sweatgland duct
Tactile corpuscle
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Hair follicle
Lamellated corpuscle
Nerve fibers
Sweat gland
Artery
Vein
Fat
Cutaneousplexus
![Page 7: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/7.jpg)
Cutaneous Membrane
Epidermis
Dermis
Papillary layer
Reticular layer
Hypodermis
![Page 8: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/8.jpg)
Accessory Structures
Hair shaft
Pore of sweatgland duct
Tactile corpuscle
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Hair follicle
Lamellated corpuscle
Nerve fibers
Sweat gland
Artery
Vein
Fat
Cutaneousplexus
![Page 9: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/9.jpg)
© 2012 Pearson Education, Inc.
Functions of Skin
o Protection of underlying tissues and organs
o Excretion of salts, water, and organic wastes (glands)
o Maintenance of body temperature (insulation and
evaporation)
o Production of melanin
![Page 10: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/10.jpg)
© 2012 Pearson Education, Inc.
Functions of Skin
o Production of keratin
o Synthesis of vitamin D3
o Storage of lipids
o Detection of touch, pressure, pain, and temperature
![Page 11: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/11.jpg)
© 2012 Pearson Education, Inc.
The Epidermis
o Is avascular stratified squamous epithelium
• Nutrients and oxygen diffuse from capillaries in the dermis
![Page 12: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/12.jpg)
Thick skin LM 154
Epidermalridge
Dermalpapilla
Stratumlucidum
Stratumcorneum
Basementmembrane
Dermis
Dermis
Epidermis
Epidermalridge
Dermalpapilla
Thin skin LM 154
![Page 13: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/13.jpg)
The structural relationship andinterface between the epidermisand underlying dermis. Theproportions of the various layersdiffer with the location sampled.
Dermis
Epidermis
Epidermalridge
Dermalpapilla
![Page 14: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/14.jpg)
© 2012 Pearson Education, Inc.
Cells of the Epidermis
o Keratinocytes
• Contain large amounts of keratin
• Are the most abundant cells in the epidermis
![Page 15: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/15.jpg)
© 2012 Pearson Education, Inc.
Thin Skin
o Covers most of the body
o Has four layers of keratinocytes
Thick Skin
o Covers the palms of the hands and soles of the feet
o Has five layers of keratinocytes
![Page 16: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/16.jpg)
A micrograph ofthin skin, which covers most ofthe exposedbody surface.
Stratumcorneum
Basementmembrane
Dermis
Thin skin LM 154
![Page 17: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/17.jpg)
A micrograph of thickskin, which coversthe surface of thepalms and the solesof the feet.
Thick skin LM 154
Epidermalridge
Dermalpapilla
Stratumlucidum
Stratumcorneum
![Page 18: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/18.jpg)
© 2012 Pearson Education, Inc.
Structures of the Epidermiso The five strata of keratinocytes in thick skin
o From basal lamina to free surface
1. Stratum basale
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum
![Page 19: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/19.jpg)
Thick skin LM 210
Surface
Stratumcorneum
Stratumlucidum
Stratumgranulosum
Stratumspinosum
Stratum basale
Basementmembrane
DermisPapillary layer of dermis
![Page 20: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/20.jpg)
© 2012 Pearson Education, Inc.
Stratum Basaleo Is attached to basement membrane by
hemidesmosomes
o Forms a strong bond between epidermis and dermis
o Forms epidermal ridges (e.g., fingerprints)
o Dermal papillae (tiny mounds)
• Increase the area of basement membrane
• Strengthen attachment between epidermis and dermis
o Has many basal cells or germinative cells
![Page 21: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/21.jpg)
Thick skin SEM 25
Epidermalridge
Pores of sweatgland ducts
![Page 22: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/22.jpg)
© 2012 Pearson Education, Inc.
Specialized Cells of Stratum Basale
o Merkel cells
• Found in hairless skin
• Respond to touch (trigger nervous system)
o Melanocytes
• Contain the pigment melanin
• Scattered throughout stratum basale
![Page 23: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/23.jpg)
© 2012 Pearson Education, Inc.
Stratum Spinosum — the “spiny layer”
o Produced by division of stratum basale
o Eight to ten layers of keratinocytes bound by
desmosomes
o Cells shrink until cytoskeletons stick out (spiny)
o Continue to divide, increasing thickness of epithelium
o Contain dendritic (Langerhans) cells, active in immune
response
![Page 24: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/24.jpg)
© 2012 Pearson Education, Inc.
Stratum Granulosum — the “grainy layer”
o Stops dividing, starts producing
• Keratin • A tough, fibrous protein
• Makes up hair and nails
• Keratohyalin • Dense granules
• Cross-link keratin fibers
![Page 25: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/25.jpg)
© 2012 Pearson Education, Inc.
Cells of Stratum Granulosum
o Produce protein fibers
o Dehydrate and die
o Create tightly interlocked layer of keratin surrounded by
keratohyalin
![Page 26: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/26.jpg)
© 2012 Pearson Education, Inc.
Stratum Lucidum — the “clear layer”• Found only in thick skin
• Covers stratum granulosum
![Page 27: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/27.jpg)
© 2012 Pearson Education, Inc.
Stratum Corneum — the “horn layer”• Exposed surface of skin
• 15 to 30 layers of keratinized cells (more in the thickest
skin)
• Water resistant
• Shed and replaced every 2 weeks
![Page 28: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/28.jpg)
© 2012 Pearson Education, Inc.
Keratinization o The formation of a layer of dead, protective cells filled
with keratin
o Occurs on all exposed skin surfaces except eyes
o Skin life cycle
o It takes 15–30 days for a cell to move from stratum basale to stratum corneum
![Page 29: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/29.jpg)
© 2012 Pearson Education, Inc.
Perspirationo Insensible perspiration
• Interstitial fluid lost by evaporation through the stratum corneum
o Sensible perspiration • Water excreted by sweat glands
• Dehydration results:• From damage to stratum corneum (e.g., burns and blisters
[insensible perspiration])• From immersion in hypertonic solution (e.g., seawater
[osmosis])
![Page 30: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/30.jpg)
© 2012 Pearson Education, Inc.
Hydration
o Results from immersion in hypotonic solution (e.g.,
freshwater [osmosis])
o Causes swelling of epithelial cells and expansion of the
skin to accommodate the extra water, which appears as
wrinkly skin
o No one knows why the skin wrinkles
![Page 31: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/31.jpg)
© 2012 Pearson Education, Inc.
Skin Color is Influenced by Two Pigments
1. Carotene
2. Melanin
o Blood circulation (red blood cells)
![Page 32: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/32.jpg)
© 2012 Pearson Education, Inc.
Caroteneo Orange-yellow pigment
o Found in orange vegetables
o Accumulates in epidermal cells and fatty tissues of the
dermis
o Can be converted to vitamin A
![Page 33: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/33.jpg)
© 2012 Pearson Education, Inc.
Melanino Yellow-brown or black pigment
o Produced by melanocytes in stratum basale
o Stored in transport vesicles (melanosomes)
o Transferred to keratinocytes
![Page 34: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/34.jpg)
Melanocytes LM 600
Melanocytes in stratum basale
Melaninpigment
Basementmembrane
![Page 35: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/35.jpg)
Basementmembrane
Melanosome
Keratinocyte
Melanin pigment
Melanocyte
![Page 36: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/36.jpg)
Melanoma
Basal cell carcinoma
![Page 37: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/37.jpg)
© 2012 Pearson Education, Inc.
Function of Melanocytes
o Melanin protects skin from sun damage
o Ultraviolet (UV) radiation
• Causes DNA mutations and burns that lead to cancer and
wrinkles
o Skin color depends on melanin production, not number of
melanocytes
![Page 38: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/38.jpg)
© 2012 Pearson Education, Inc.
Capillaries and Skin Coloro Oxygenated red blood contributes to skin color
• Blood vessels dilate from heat, skin reddens
• Blood flow decreases, skin pales
o Cyanosis• Bluish skin tint
• Caused by severe reduction in blood flow or oxygenation
![Page 39: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/39.jpg)
© 2012 Pearson Education, Inc.
Illness and Skin Coloro Jaundice
• Buildup of bile produced by liver
• Yellow color
o Pituitary tumor• Excess MSH (melanocyte stimulating hormone)
o Addison’s disease• A disease of the pituitary gland
• Skin darkening
o Vitiligo• Loss of melanocytes
• Loss of color
![Page 40: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/40.jpg)
© 2012 Pearson Education, Inc.
Vitamin D3
o Epidermal cells produce cholecalciferol (vitamin D3)
• In the presence of UV radiation
o Liver and kidneys convert vitamin D3 into calcitriol
• Aids absorption of calcium and phosphorus
o Insufficient vitamin D3
• Can cause rickets and depressed immune system
• Has been shown as a potential treatment for MS (in
conjuction with traditional treatments)
• Low levels appear in those with some cancers
![Page 41: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/41.jpg)
![Page 42: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/42.jpg)
© 2012 Pearson Education, Inc.
Epidermal Growth Factor (EGF) o Powerful growth factor
o Produced by glands (salivary and duodenum)
o Used in laboratories to grow skin grafts
Functions of EGFo Promotes division of germinative cells
o Accelerates keratin production
o Stimulates epidermal repair
o Stimulates glandular secretion
![Page 43: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/43.jpg)
© 2012 Pearson Education, Inc.
The Dermiso Located between epidermis and subcutaneous layer
o Anchors epidermal accessory structures (hair follicles, sweat glands)
o Two components
1. Outer papillary layer
2. Deep reticular layer
![Page 44: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/44.jpg)
© 2012 Pearson Education, Inc.
The Papillary Layero Consists of areolar tissue
o Contains smaller capillaries, lymphatics, and sensory
neurons
o Has dermal papillae projecting between epidermal
ridges
![Page 45: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/45.jpg)
© 2012 Pearson Education, Inc.
The Reticular Layero Consists of dense irregular connective tissue
o Contains larger blood vessels, lymphatic vessels, and
nerve fibers
o Contains collagen and elastic fibers
o Contains connective tissue proper
![Page 46: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/46.jpg)
© 2012 Pearson Education, Inc.
Dermatitiso An inflammation of the papillary layer
o Caused by infection, radiation, mechanical irritation, or
chemicals (e.g., poison ivy)
o Characterized by itch or pain, redness, and/or flaky skin
![Page 47: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/47.jpg)
© 2012 Pearson Education, Inc.
Dermal Strength and Elasticityo Presence of two types of fibers
1. Collagen fibers• Very strong, resist stretching but bend easily• Provide flexibility
2. Elastic fibers• Permit stretching and then recoil to original
length• Limit the flexibility of collagen fibers to prevent
damage to tissue• Skin turgor
• Properties of flexibility and resilience
![Page 48: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/48.jpg)
© 2012 Pearson Education, Inc.
Skin Damageo Sagging and wrinkles (reduced skin elasticity) are
caused by:
• Dehydration
• Age
• Hormonal changes
• UV exposure
![Page 49: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/49.jpg)
© 2012 Pearson Education, Inc.
Skin Damageo Stretch marks
• Thickened tissue resulting from excessive stretching
of skin due to:
• Pregnancy
• Weight gain
![Page 50: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/50.jpg)
© 2012 Pearson Education, Inc.
Cleavage Lineso Collagen and elastic fibers in the dermis
• Arranged in parallel bundles
• Resist force in a specific direction
o Cleavage (tension) lines establish important patterns• A parallel cut remains shut, heals well
• A cut across (right angle) pulls open and scars
![Page 51: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/51.jpg)
ANTERIOR POSTERIOR
![Page 52: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/52.jpg)
© 2012 Pearson Education, Inc.
The Dermal Blood Supplyo Cutaneous plexus
• A network of arteries along the reticular layer
o Papillary plexus • Capillary network from small arteries in papillary layer
o Venous plexus• Capillary return deep to the papillary plexus
o Contusion• Damage to blood vessels resulting in “black-and-blue”
bruising
![Page 53: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/53.jpg)
Hair
Papillarylayer
Reticularlayer
Cutaneousplexus
Papillaryplexus
Epidermalridges
Dermalpapillae
Capillary loopof papillary
plexus
![Page 54: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/54.jpg)
© 2012 Pearson Education, Inc.
Innervation of the Skin
o Nerve fibers in skin control:
• Blood flow
• Gland secretions
• Sensory receptors • Light touch—tactile corpuscles, located in dermal papillae• Deep pressure and vibration—lamellated corpuscles, in the
reticular layer
![Page 55: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/55.jpg)
© 2012 Pearson Education, Inc.
The Hypodermis (Subcutaneous Layer)o Lies below the integument
o Stabilizes the skin
o Allows separate movement
o Made of elastic areolar and adipose tissues
o Connected to the reticular layer of integument by connective tissue fibers
o Few capillaries and no vital organs
o The site of subcutaneous injections using hypodermic needles
![Page 56: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/56.jpg)
© 2012 Pearson Education, Inc.
Deposits of Subcutaneous Fato Distribution patterns determined by hormones
o Reduced by cosmetic liposuction (lipoplasty)
![Page 57: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/57.jpg)
© 2012 Pearson Education, Inc.
Hair, Hair Follicles, Sebaceous Glands,
Sweat Glands, and Nailso Integumentary accessory structures
o Derived from embryonic epidermis
o Located in dermis
o Project through the skin surface
![Page 58: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/58.jpg)
© 2012 Pearson Education, Inc.
Human Bodyo The human body is covered with hair, except:
• Palms
• Soles
• Lips
• Portions of external genitalia
![Page 59: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/59.jpg)
© 2012 Pearson Education, Inc.
Functions of Hairo Protects and insulates
o Guards openings against particles and insects
o Is sensitive to very light touch
![Page 60: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/60.jpg)
© 2012 Pearson Education, Inc.
The Hair Follicleo Located deep in dermis
o Produces nonliving hairs
o Wrapped in a dense connective tissue sheath
o Base is surrounded by sensory nerves (root hair
plexus)
![Page 61: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/61.jpg)
© 2012 Pearson Education, Inc.
Accessory Structures of Hairo Arrector pili
• Involuntary smooth muscle
• Causes hairs to stand up
• Produces “goose bumps”o Sebaceous glands
• Lubricate the hair
• Control bacteria
![Page 62: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/62.jpg)
© 2012 Pearson Education, Inc.
Regions of the Hair
o Hair root
• Lower part of the hair
• Attached to the integument
o Hair shaft
• Upper part of the hair
• Not attached to the integument
![Page 63: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/63.jpg)
Single hair follicle, showingthe associated accessorystructures; a superficialview of the deeper portionsof the follicle illustrates theconnective tissue sheathand the root hair plexus.
Exposedshaftof hair
Sebaceousgland
Arrectorpilimuscle
Connectivetissue sheath
Root hairplexus
![Page 64: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/64.jpg)
Cross section through ahair follicle and a hair, nearthe junction between thehair root and hair shaft.
Connective tissue sheath
Hair Structure
Follicle Structure
The medulla, or
core, of the hair
contains a flexible
soft keratin.
The cortex contains thick
layers of hard keratin,
which give the hair its stiff-
ness.
The cuticle, although
thin, is very tough, and
it contains hard keratin.
The internal root sheath surroundsthe hair root and the deeper portion ofthe shaft. The cells of this sheathdisintegrate quickly, and this layer doesnot extend the entire length of the hairfollicle.
The external root sheath extendsfrom the skin surface to the hair matrix.
The glassy membrane is a thickened,clear layer wrapped in the denseconnective tissue sheath of the follicleas a whole.
![Page 65: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/65.jpg)
Diagrammatic sectionalview along the long axisof a hair follicle.
Boundary betweenhair shaftandhair root
Hair shaft
Sebaceousgland
Arrectorpili muscle
Hair root
Connectivetissue sheath
Hair bulb
Hair matrix
Hair papilla
![Page 66: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/66.jpg)
Longitudinal section through twohair follicles, showing the base ofthe follicle and the matrix andpapilla at the root of the hair.
Sebaceous gland
Hair shaft
Hair
Glassy membrane
Subcutaneous adiposetissue
Connective tissue sheathof hair
Cortex
Medulla
Hair matrixPapillaHair bulb
![Page 67: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/67.jpg)
© 2012 Pearson Education, Inc.
Hair Production
o Begins at the base of a hair follicle, deep in the dermis
• The hair papilla contains capillaries and nerves
• The hair bulb produces hair matrix
• A layer of dividing basal cells
• Produces hair structure
• Pushes hair up and out of skin
![Page 68: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/68.jpg)
© 2012 Pearson Education, Inc.
Hair Shaft Structure
o Medulla
• The central core
o Cortex
• The middle layer
o Cuticle
• The surface layer
![Page 69: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/69.jpg)
© 2012 Pearson Education, Inc.
Keratino As hair is produced, it is keratinized
• Medulla contains flexible soft keratin
• Cortex and cuticle contain stiff hard keratin
![Page 70: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/70.jpg)
© 2012 Pearson Education, Inc.
Hair Growth Cycleo Growing hair
• Is firmly attached to matrix
• Club hair
• Is not growing because it is in its final
stage of growth
• Is attached to an inactive follicle
• Once the club hair is gone, no more hair
will emerge from that follicle
![Page 71: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/71.jpg)
© 2012 Pearson Education, Inc.
Hair Growth Cycleo New hair growth cycle
• Follicle becomes active
• Produces new hair
• Club hair is shed
![Page 72: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/72.jpg)
© 2012 Pearson Education, Inc.
Types of Hairs
o Vellus hairs
• Soft, fine
• Cover body surface
o Terminal hairs
• Heavy, pigmented
• Head, eyebrows, and eyelashes
• Other parts of body after puberty
![Page 73: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/73.jpg)
© 2012 Pearson Education, Inc.
Hair Color
o Produced by melanocytes at the hair papilla
o Determined by genes
![Page 74: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/74.jpg)
© 2012 Pearson Education, Inc.
Exocrine Glands in Skino Sebaceous Glands (oil glands)
• Holocrine glands
• Secrete sebum
o Two Types of Sweat Glands
1. Apocrine glands
2. Merocrine (eccrine) glands
• Watery secretions
![Page 75: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/75.jpg)
© 2012 Pearson Education, Inc.
Types of Sebaceous (Oil) Glandso Simple branched alveolar glands
• Associated with hair follicles
o Sebaceous follicles
• Discharge directly onto skin surface
• Sebum
• Contains lipids and other ingredients
• Lubricates and protects the epidermis
• Inhibits bacteria
![Page 76: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/76.jpg)
Epidermis
Dermis
Subcutaneouslayer
Sebaceous follicle Sebaceous gland
Sebaceous gland LM 150
Basal cells
Mitosis and growth
Breakdown ofcell membranes
Lumen
Discharge ofsebum
Basementmembrane
Lumen(hair removed)
Wall of hair follicle
![Page 77: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/77.jpg)
Epidermis
Dermis
Subcutaneouslayer
Sebaceous follicle Sebaceous gland
![Page 78: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/78.jpg)
Basal cells
Mitosis and growth
Breakdown ofcell membranes
Lumen
Discharge ofsebum
Basementmembrane
Lumen(hair removed)
Wall of hair follicle
![Page 79: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/79.jpg)
Basal cells
Basementmembrane
Lumen(hair removed)
Wall of hair follicle
Sebaceous gland LM 150
![Page 80: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/80.jpg)
© 2012 Pearson Education, Inc.
Apocrine Sweat Glands
o Found in armpits, around nipples, and groin
o Secrete products into hair follicles
o Produce sticky, cloudy secretions
o Break down and cause odors
o Surrounded by myoepithelial cells
• Squeeze apocrine gland secretions onto skin surface
• In response to hormonal or nervous signal
![Page 81: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/81.jpg)
Apocrine sweat glandssecrete a thick, odorousfluid into hair follicles.
LM 459Apocrine sweat gland
Lumen
Myoepithelial cell
Connectivetissue of dermis
Apocrinegland cells
Duct ofapocrine
sweat gland
Sectional planethrough apocrine
sweat gland
A sectionthrough a merocrinesweat gland
Sweat pore
Duct
![Page 82: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/82.jpg)
© 2012 Pearson Education, Inc.
Merocrine (Eccrine) Sweat Glands o Widely distributed on body surfaceo Especially on palms and soleso Coiled, tubular glandso Discharge directly onto skin surfaceo Sensible perspirationo Water, salts, and organic compoundso Functions of merocrine sweat gland activity
• Cools skin• Excretes water and electrolytes• Flushes microorganisms and harmful chemicals from
skin
![Page 83: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/83.jpg)
Duct ofapocrine
sweat gland
Sectional planethrough apocrine
sweat gland
A sectionthrough a merocrinesweat gland
Sweat pore
Duct
Merocrine sweat glandsdischarge a watery fluidonto the surface of theskin.
LM 243Merocrinesweat gland
Lumen
Myoepithelialcells
Merocrinegland cells
![Page 84: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/84.jpg)
© 2012 Pearson Education, Inc.
Other Integumentary Glands
1. Mammary glands
• Produce milk
2. Ceruminous glands
• Produce cerumen (earwax)
• Protect the eardrum
![Page 85: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/85.jpg)
© 2012 Pearson Education, Inc.
Control of Glandso Autonomic nervous system (ANS)
• Controls sebaceous and apocrine sweat glands• Works simultaneously over entire body
o Merocrine sweat glands• Controlled independently• Sweating occurs locally
o Thermoregulation• The main function of sensible perspiration• Works with cardiovascular system• Regulates body temperature
![Page 86: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/86.jpg)
© 2012 Pearson Education, Inc.
Nails
o Protect fingers and toes
o Made of dead cells packed with keratin
o Metabolic disorders can change nail structure
Nail Production
o Occurs in a deep epidermal fold near the bone called the
nail root
![Page 87: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/87.jpg)
A longitudinal section
A superficial view
A cross-sectional viewEponychium
Proximalnail fold
Lunula
Nail body
Lateral nail fold
Free edge
Directionof growth
Nailbody
Lateralnail
groove
Nailbed
Phalanx(bone of
fingertip)
Eponychium
Proximal nail fold
Nail root
Lunula Nail body
Epidermis Dermis Phalanx Hyponychium
![Page 88: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/88.jpg)
© 2012 Pearson Education, Inc.
Repair of the Integument Following an Injuryo Bleeding occurs
o Mast cells trigger inflammatory response
o A scab stabilizes and protects the area
o Germinative cells migrate around the wound
o Macrophages clean the area
o Fibroblasts and endothelial cells move in, producing
granulation tissue
![Page 89: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/89.jpg)
Bleeding occurs at the siteof injury immediately afterthe injury, and mast cellsin the region trigger aninflammatory response.
Epidermis
Dermis
Mast cells
![Page 90: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/90.jpg)
After several hours, ascab has formed and cellsof the stratum basale aremigrating along the edges of the wound. Phagocyticcells are removing debris,and more of these cellsare arriving via theenhanced circulation inthe area. Clotting aroundthe edges of the affectedarea partially isolates theregion.
Migratingepithelialcells
Macrophagesand fibroblasts
Granulationtissue
![Page 91: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/91.jpg)
Fibroblasts
One week after the injury,the scab has beenundermined by epidermalcells migrating over themeshwork produced byfibroblast activity.Phagocytic activityaround the site hasalmost ended, and thefibrin clot is breaking up.
![Page 92: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/92.jpg)
Scartissue
After several weeks, thescab has been shed, andthe epidermis is complete.A shallow depressionmarks the injury site, butfibroblasts in the dermiscontinue to create scartissue that will graduallyelevate the overlyingepidermis.
![Page 93: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/93.jpg)
© 2012 Pearson Education, Inc.
Repair of the Integument Following an Injury
o Fibroblasts produce scar tissue
• Inflammation decreases, clot disintegrates
• Fibroblasts strengthen scar tissue
• A raised keloid may form, which is an overgrowth of
collagen during the healing process
![Page 94: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/94.jpg)
![Page 95: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/95.jpg)
Head 9%
Upper limb9% each
Trunk 36%(front and back)
Genitalia 1%
Lower limb18% each
Head 15%
Trunk 32%(front and back)
Lower limb17% each
Upper limb 9% each
Genitalia 1%
ADULT CHILD (5-year-old)
![Page 96: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/96.jpg)
© 2012 Pearson Education, Inc.
Effects of Aging
o Epidermal thinning
o Decreased numbers of dendritic (Langerhans) cells
o Decreased vitamin D3 production
o Decreased melanocyte activity
o Decreased glandular activity (sweat and oil glands)
![Page 97: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/97.jpg)
© 2012 Pearson Education, Inc.
Effects of Aging
o Reduced blood supply
o Decreased function of hair follicles
o Reduction of elastic fibers
o Decreased hormone levels
o Slower repair rate
![Page 98: © 2012 Pearson Education, Inc. The Integument o Is the largest system of the body 16% of body weight 1.5 to 2 m 2 in area The integument is made up of.](https://reader035.fdocuments.us/reader035/viewer/2022070407/56649e105503460f94afbc47/html5/thumbnails/98.jpg)
© 2012 Pearson Education, Inc.
Importance of the Integumentary System
o Protects and interacts with all organ systems
o Changes in skin appearance are used to diagnose
disorders in other systems