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Copyright © 2010 Pearson Education, Inc.
Integumentary System
What is the function of the integumentary system?
Copyright © 2010 Pearson Education, Inc.
Incredible Human Machine: Skin
• Write down 3 interesting facts, be prepared to share your responses with the rest of the class.
• https://www.youtube.com/watch v=fXIcwm1oqQw
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Integumentary System
• Major parts:
1. Cutaneous membrane (skin)
• epidermis (epithelium)
• dermis (CT)
• subcutaneous layer (hypodermis)
– loose CT, attaches integument to structures
2. Accessory Structures – hair, nails, exocrine glands
• Anchored in dermis & extend up thru epidermis
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Integumentary System
• 6 major functions:
– Protects & prevents H20 loss
– Temp. maintenance (insulation & evaporation)
– Synthesizes vitamin D3
– Storage (adipose tissue)– Sensory reception– Excretion & secretion of salts, water, wastes by glands
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Figure 5-1
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BR: Write down the following words.
• Subcutaneous fat• Epidermis• Dermis• Melanin• Oil glands• Sebum
• Pores• Hair• Erector Pili• Pilometer reflex• Sweat glands
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Epidermis
• Stratified squamous
epithelium
– nutrients & O2 diffuse
from capillaries in dermis
• Thin Skin - 4 layers
(strata)
• Thick Skin - 5 layers
– Palms & soles of feet
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Epidermis
• 5 strata: (CELL LAYERS)
1. Stratum germinativum
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum
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Stratum corneum Stratum granulosumStratum lucidum
Stratum spinosum
Dermis Epidermal Ridge Dermal papillae
Stratum germinativum
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Epidermis
1. Stratum germinativum
– contains germinative (stem) cells & melanocytes
– forms epidermal ridges (extend into dermis) & dermal
papillae (extend toward surface)
• ↑ SA for diffusion
2. Stratum Spinosum– cells may continue to divide
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Epidermis
3. Stratum Granulosum
– cells produce keratin – durable, H2O-resistant protein
• forms hair, nails, calluses
4. Stratum Lucidum (ONLY in thick skin)– thin cells filled w/ keratin
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Epidermis
5. Stratum corneum
– 15-30 layers of dead keratinized cells
– shed & replaced every 2 weeks
– dry, oily surface inhibits microbial growth
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BR
• Turn in Bell Ringers & Epidermis Chart
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Skin Color• Carotene (orange-yellow)
– converted to vitamin A
• Melanin (yellow-brown or black)– stored in melanosomes
– produced by melanocytes• protects skin by absorbing
UV radiation– causes DNA mutations
& burns – skin color depends on
amount of melanin production
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Figure 5-3
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Skin Color
• Blood vessels dilate from heat skin reddens
• Blood flow to surface ↓’s skin pales
• Cyanosis: bluish skin tint
– caused by severe ↓ in blood flow or oxygenation
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Effects of Sunlight
• Vitamin D3
– produced by epidermal cells
– liver & kidneys convert vitamin D3 into calcitriol
• aids absorption of Calcium
– insufficient vitamin D3 can cause rickets (abnormally weak,
flexible bones)
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Effects of Sunlight
• Skin Cancers
a. Basal cell carcinoma – most common
– originates in stratum germ.
b. Squamous cell carcinoma
– superficial layers of epidermis
c. Malignant melanoma – more dangerous
– cancerous melanocytes metastasize thru lymphoid system
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The Dermis
1. Papillary Layer• Loose CT
2. Reticular Layer• dense irregular CT• Collagen & elastin
Both contain blood & lymph vessels, nerve fibers.
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Hypodermis: Subcutaneous
– Allows independent movement
– Shock absorption & E storage
– has few capillaries & no vital organs site of subcutaneous injections
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Hair
• Fxns:
– protects & insulates
– Guards against foreign
particles
– Sensitive to very light
touch (warning system)
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Figure 5-5
• papilla: CT containing capillaries &
nerves
– stem cells surrounding hair
papilla form hair
• root: anchors hair into skin
• shaft: part of hair on surface
• arrector pili muscle: causes
goose bumps
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Hair Follicles
Figure 5-5
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Exocrine Glands
1. Sebaceous (Oil) Glands (holocrine)
– discharge sebum into hair follicles or directly onto
skin
• Lubricates and inhibits bacterial growth
• Cause Acne
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Exocrine Glands2. Sweat Glands
Apocrine• secrete products into
hair follicles• sticky, cloudy
secretion • can cause odors• Armpits, groin, &
around nipples
Merocrine (Eccrine)• discharge directly onto
skin, cool the body• H20 (99%), electrolytes,
organic nutrients, waste products (urea), dermicidin (antibiotic)
• flush microorganisms & chemicals from skin
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Figure 5-7
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Nails
• Nail body consists of dead, keratinized cells
• nail growth occurs at nail root (epidermal fold below surface)
Figure 5-8
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Repair
Figure 5-9
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Repair
Figure 5-9
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Repair of Skin Injuries
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Effects of Aging• epidermis thins skin injuries & infections more common• dermis thins sagging & wrinkling of skin
• vitamin D3 production ↓’s weaker muscles & bones
• melanin production ↓’s • gland activity ↓’s skin becomes dry & scaly• hair thins & loses color• blood supply to skin ↓’s, sweat glands less active ability
to release heat ↓’s• skin repairs more slowly
The Integumentary System in Perspective
Functional Relationships Between the Integumentary System and Other Systems
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• The Skeletal System provides structural support• The Integumentary System
synthesizes vitamin D3, essential for calcium and phosphorus absorption (bone maintenance and growth)
The Skeletal System
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The Muscular System
• The Muscular System’s facial muscles pull against skin of face, producing expressions important in communication
• The Integumentary System synthesizes vitamin D3 , essential for normal calcium absorption (calcium ions play an essential role in muscle contraction)
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The Nervous System
• The Nervous System controls blood flow and sweat gland activity for thermoregulation; stimulates contraction of arrector pili muscles to elevate hairs
• The Intergumentary System’s receptors in dermis and deep epidermis provide sensations of touch, pressure, vibration, temperature, and pain
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The Endocrine System
• The Endocrine System includes the sex hormones that stimulate sebaceous and apocrine gland activity, and develop secondary sexual characteristics; suprarenal hormones alter blood flow to skin and mobilize lipids from fat cells
• The Integumentary System synthesizes vitamin D3, precursor of calcitriol, a hormone produced by the kidneys
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The Cardiovascular System
• The Cardiovascular System provides oxygen and nutrients; delivers hormones and cells of immune system; carries away carbon dioxide, waste products, and toxins; provides heat to maintain normal skin temperature
• The Integumentary System’s mast cells produce localized changes in blood flow and capillary permeability
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The Lymphatic System
• The Lymphoid System assists in defending the integument by providing additional macrophages and mobilizing lymphocytes
• The Integumentary System provides physical barriers that prevent pathogen entry; macrophages resist infection; mast cells trigger inflammation and initiate the immune reponse
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The Respiratory System
• The Respiratory System provides oxygen and eliminates carbon dioxide
• The Integumentary System’s hairs guard entrance to nasal cavity
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The Digestive System
• The Digestive System Provides nutrients for all cells and lipids for storage by adipocytes
• The Integumentary System synthesizes vitamin D3, needed for absorption of calcium and phosphorus
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The Urinary System
• The Urinary System excretes waste products, maintains normal body fluid pH and ion composition
• The Integumentary System assists in elimination of water and solutes; keratinized epidermis limits fluid loss through skin
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The Reproductive System
• The Reproductive System’s sex hormones affect hair distribution, adipose tissue distribution in subcutaneous layer, and mammary gland development
• The Integumentary System covers external genitalia; provides sensations that stimulate sexual behaviors; mammary gland secretions provide nourishment for newborn infant
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