1. INTEGUMENTARY SYSTEM

2. Structure and Function
Integumentary system is composed of the skin and accessory structures (hair, hair follicles, nails, glands & nerves)
Functions of the integumentary system
Protects the other body systems from injury and infection:
Mechanical damage (cuts & bruises)
Chemical damage (acids & bases)
Thermal damage (heat & cold)
Ultraviolet damage (sunlight)
Defense against microorganisms
Helps the body maintain homeostasis by regulating temperature, retaining body fluids, and eliminating wastes
Insulates and cushions deeper organs

3. Figure 9-1 Skin Structures

4. Skin The largest organ of the body 21 sq feet, 1.5 – 2 sq meters
4 kilograms, 9 pds, 7-15% of total body weight
Varies in thickness from 1/50 inch (0.5 mm) in the eyelids to 1/4 inch (6.3 mm) in the soles of the feet
Changes in the skin often indicate the presence of other body system disorders including anemia, respiratory disorders, liver disorders, cancer, and shock
Each inch of skin contains 15 ft of blood vessels
The body sloughs off about 500 million cells a day; 1 ½ pounds per year

5. Skin (cutaneous)
The top layer is full of keratin and hardened (cornified) to prevent water loss
The rich capillary network and sweat glands help regulate heat loss from surface
It is a mini-excretory system- loses urea, water and salts
Manufactures proteins important to immunity and synthesizes Vitamin A, D & K. (vit D synthesis very important)
Cutaneous sensory receptors
provide info about the
environment

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Layers of Skin
Epidermis
- it is avascular
Outermost layer of the skin that is composed of a surface of dead cells with an underlying layer of living cells; complete regeneration appox 35 days and is derived from the stratum basale layer
Made up of stratified squamous cells that are capable of keratinizing (hard/tough)
Melanocytes (pigment cells); increase in sun exposure will cause these cells to produce more melanin
Langerhans cells: macrophages that activate the immune system
Merkel cells: sensory nerve receptors
Copyright 2003 by Mosby, Inc. All rights reserved.

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Layers of Skin
Dermis (corium or true skin)
Called the “true” skin; the dermis contains the blood vessels and nerves
Dense Connective tissue; strong/flexible
Collagen, elastin (stretch/recoil)
Contains:
Blood vessels and capillaries
Lymphatic vessels
Nerves
Hair shafts and hair follicles
Sensory receptors
Sudorferous glands- sweat
Sebaceous glands- oil
**The epidermis and dermis are firmly connected
but can be separated by friction
(blisters) Dense Connective tissue
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8. Layers of Skin Subcutaneous- hypodermis Not skin
Adipose and areolar connective tissue
Stores fat
Anchors skin to underlying structures (muscles)
Allows skin to slide freely
Shock absorber, insulator
Thickens with weight gain

9. Types of Skin Thick skin- only on palms & soles
Thick epidermis (.6-4.5mm) distinct stratum lucidum & thick stratum corneum
Lacks hair follicles & sebaceous glands
Thin skin- covers most of the body
Thin epidermis (.1-.15mm) lacks stratum lucidum
Lacks epidermal ridges, fewer sweat glands & sensory receptors

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Skin
Stretch marks- extreme stretching that produces a silvery white scar
Blister- separation of epidermal and dermal layers by fluid filled pocket
Flexure lines- skin markings; dermal folds at or near a joint; deep creases
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Skin Color
Pigments:
Keratin
Yellow to orange
Accumulates in stratum corneum and fatty tissue of hypodermis
Color obvious in palms and soles
Melanin
Only pigment in the skin
Yellow to reddish-brown to black
Synthesis depends on enzyme in melanocytes
Racial differences vary on amount of melanin made
Local accumulation in freckles and moles
Exposure to sunlight increases manufacturing of melanin to prolonged exposure; tan
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12. Abnormal color/homeostatic imbalances
Pallor (blanching)
Emotional distress, anemia, low BP
Erythema (redness)
Congestion of blood in vessels
Burns
Embarrassment (blushing)
Fever
Hypertension
Inflammation
Allery

13. Abnormal color/homeostatic imbalances
Bruises
Blood escapes and clots under skin, hematoma, vit c deficiency
hemophilia
Albinism
Absence of pigment color
Vitiligo
Loss of pigment in certain areas, usually acquired
Gray/Brown
Chronic poisonings
Cyanosis (blue)
Insufficient oxygen
Bronzing (metallic)
Addison’s disease (hypofunction of adrenal cortex)
Jaundice (yellow)
Liver disorder, biliary disorder, presence of bile in blood,
diseases involving destruction of RBCs

14. Skin Injuries Excessive sun exposure
Clumps elastin fibers “leathery skin”
Temporary depression
of immune system
-DNA alteration (cancer)
Type 1- very fair
Type 2- tans minimally
Type 3- tans gradually
Type 4- medium skin
Type 5- rarely burns (dark)
Type 6- never burns (very dark)

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Skin Injuries
Blisters: injury damages chemical bond of skin layers at dermal/epidermal junction
Callous: abnormally thick stratum corneum
Burns:1st, 2nd, 3rd & 4th degree depending on depth of burn (UV light, corrosive chemicals, electricity)
Copyright 2003 by Mosby, Inc. All rights reserved.

16. Accessory Structures
Hair/Hair follicle
Glands
Nails
Nerves

17. Hair and Hair Follicles
Skin has hair in all areas except the soles of the feet and palms of the hands
Composed of keratin and proteins; also dead epidermal cells
Hair serves to block foreign particles from entering the body through structures such as the nose and eyes
The visible portion is called the shaft
The hair follicle is the root with its covering
Anagen: growing follicle
Telogen: resting follicle

18. Hair Growth: Arrection Pili= hair muscles
Lanugo: fetal hair and lost at birth
Puberty: coarse hair; grows ½” per month
Arrection Pili= hair muscles
This is a tiny muscle that attaches to the base of a hair follicle at one end and to dermal tissue on the other end.  In order to generate heat when the body is cold, the arrector pili muscles contract all at once, causing the hair to "stand up straight" on the skin.  The arrector pili muscle is a source of information when evaluating a skin biopsy since it is well-innervated with autonomic nerves that control when the muscle contracts.

19. Nails Tightly packed, keratinized cells Nail body is pink due to
underlying capillaries
Free edge appears white
Lunula is white due to
thickened stratum basale
Cuticle (eponychium)
Nail root- buried under skin layers

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Glands
Four types of glands in the skin (exocrine)
Sebaceous glands (oil)
Sudoriferous glands (sweat)
Ceruminous glands (wax)
Mammary (milk) glands
Function is to help regulate the body temperature and excrete body wastes
Copyright 2003 by Mosby, Inc. All rights reserved.

21. Sebaceous (Oil) glands
Secretory in dermis- open into hair shafts
Acne- bacterial inflammation of glands
Secretions stimulated by hormones at puberty
Associated with blackheads
Sebum- combination of cholesterol, proteins, fats, and salts
Keeps hair/skin soft and pliable
Inhibits growth of bacteria and fungi
Copyright 2003 by Mosby, Inc. All rights reserved.

22. Sebaceous glands

23. Sudoriferous (sweat) glands
Apocrine (sweat) glands- secrete at hair follicle and active at puberty
In dermis with ducts that open into hair follicles
-Axilla (underarm)
Perianal (near the anal area)
Areole, (nipple)
Periumbilical (around the belly button),
External ear canal,
Eyelids
Also consists of ducts and secretory coils, but these glands are larger than eccrine glands and open onto hair follicles.
Eccrine (sweat glands)
Most areas of the body
In dermis with ducts to surface
Regulates body temp w/ perspiration
*produces about 500 mL p/day

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Sudorfierous glands
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25. Ceruminous glands (wax)
Modified sweat glands
Located in auditory canal
Cerumen- contains secretions of oil and wax glands; barrier for entrance of foreign bodies
Impacted cerumen may reduce hearing

26. Disorders of the Integumentary System
Acne vulgaris
– Caused by increased secretion of oil related to increased hormones during puberty
Albinism
– Inherited disorder in which melanin is not produced
Alopecia
– Baldness
Athlete’s foot
– Contagious fungal infection of the foot

27. Disorders of the Integumentary System (continued)
Cellulitis
– Bacterial infection of the dermis and subcutaneous layer of the skin
Chloasma
– Patchy discoloration of the face
Cleft lip or cleft palate
– Upper lip has a cleft where the nasal palate doesn’t meet properly
Contact dermatitis
– Allergic reaction that may occur after initial contact or as an acquired response

28. Disorders of the Integumentary System
Dandruff
– White flakes of dead skin cells from the scalp
Decubitus ulcers (bed sores)
– Sores or areas of inflammation that occur over bony prominences of the body
Eczema
– Group of disorders caused by allergic or irritant reactions; red, dry, itchy, scaly skin
Fungal skin infections
– Skin infections that live on dead outer surface or epidermis

29. Disorders of the Integumentary System (continued)
Furuncle
– Boil, or bacterial infection of a hair follicle
Hirsutism
– Abnormal amount of hair growth in unusual places
Impetigo
– Very contagious bacterial (staph or strep) skin infection that occurs most often in children
Kaposi’s sarcoma
– Form of cancer that originates in blood vessels and spreads to skin

30. Disorders of the Integumentary System
Lupus
– Benign dermatitis or chronic systemic disorder
Psoriasis
– Chronic skin disorder in which too many epidermal cells are produced
Rashes
– May result from viral infection, especially in children
- Rhinoplasty- surgical repair of the nose
-Ring Worm
-Fungal infection on surface of skin; contagious and treated with antifungal
Scleroderma
– Rare autoimmune disorder that affects blood vessels and connective tissues of the skin
*Tinea pedis -Athletes foot; fungal infection

31. Disorders of the Integumentary System (continued)
Skin cancer
– Three forms are basal, squamous, and melanoma; **basal cell is most common
Skin lesions
– Differ in texture, color, location, and rate of growth
Streptococcus
– Nonmotile bacteria that affect many parts of the body

32. Disorders of the Integumentary System (continued)
Vitiligo
– Condition that causes loss of pigment in the skin
Wart
– Papule caused by a viral infection

33. Issues and Innovations
Skin and hair care
– Skin care products include soap, astringents, and cosmetics
– Ways to remove hair include wax, depilatory creams, and electrolysis
• Sun and skin cancer
– Damage by ultraviolet rays
– Types of skin cancer

34. Warning Signs of Melanoma
-Change in size and pigmented spot or mole
-Change in color of an existing mole
-Change in consistency of shape of the skin over the pigmented spot
-Inflammation of the skin around an existing mole

35. Melanoma