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Chapter 6

The Skin in Health The Skin in Health and Diseaseand Disease

Martin Ponciano, LVN, MS, DSDMartin Ponciano, LVN, MS, DSD

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Objectives:

• Name and describe the layers of the skin

• Describe the subcutaneous tissue

• Give the location and function of the accessory structures of the skin

• List the principal functions of the skin

• Summarize the information gained by observation of the skin

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The Integumentary SystemThe Integumentary System

Skin and associated structures form integumentary system

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Structure of the SkinStructure of the Skin

Skin consists of two layers• Epidermis

• Strata• Dermis

• Blood vessels, nerve endings, and glands

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Cross section of the skin.

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Epidermis

Surface portion of the skin• Stratum basale or stratum germinativum• Stratum corneum

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Dermis

Contains most of the accessory structures of the skin• Blood vessels• Nerves• Sweat glands• Oil glands• Hair• Dermal papillae

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Checkpoint 6-1: The skin and all its associated structures comprise a body system. What is the name of this system?Checkpoint 6-2: The skin itself is composed of two layers. Moving from the superficial to the deeper layer, what are the names of these two layers?

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Subcutaneous Layer

Connects the skin to the surface muscles• Loose connective tissue• Adipose (fat) tissue• Blood vessels• Nerves and nerve endings

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Checkpoint 6-3: What is the composition of the subcutaneous layer?

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Accessory Structures Accessory Structures of the Skinof the Skin

Some structures of the integumentary system protect the skin and have some more generalized functions as well

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Sebaceous (Oil) Glands

Produce a variety of secretions• Sebum• Vernix caseosa• Eye lubrication

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Sudoriferous (Sweat) Glands

Located in the dermis and subcutaneous tissue• Eccrine type sweat glands• Apocrine sweat glands• Ceruminous glands• Ciliary glands• Mammary glands

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Checkpoint 6-4: Some skin glands produce an oily secretion called sebum. What is the name of these glands?

Checkpoint 6-5: What is the scientific name for the sweat glands?

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Hair

Composed mainly of keratin and is not living• Hair follicles• Melanocytes• Arrector pili

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Portion of skin showing associated glands and hair.ZOOMING IN • How do the sebaceous glands and apocrine sweat glands secrete to the outside? What kind of epithelium makes up the sweat glands?

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Checkpoint 6-6: Each hair develops within a sheath. What is this sheath called?

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Nails

Made of keratin produced by cells that originate in the outer layer of the epidermis• Nail root• Nail plate• Nail bed• Lunula• Cuticle

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Nail structure.

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Functions of the SkinFunctions of the Skin

Four major functions• Protection against infection• Protection against dehydration (drying)• Regulation of body temperature• Collection of sensory information

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Protection Against Infection

Intact skin forms a primary barrier against invasion• Interlocking pattern resists penetration• Shedding removes pathogens• Protects against bacterial toxins• Protects against some harmful environmental

chemicals

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Protection Against Dehydration

Skin prevents water loss by evaporation• Keratin in the epidermis• Sebum release from the sebaceous glands

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Regulation of Body Temperature

Loss of excess heat and protection from cold are important functions of the skin• Constriction of blood vessels• Dilation of blood vessels• Evaporation of perspiration

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Collection of Sensory Information

Skin has many nerve endings and other special receptors• Free nerve endings• Touch receptors• Deep pressure receptors

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Other Activities of the Skin

• Absorption of substances such as medications• Excretion

• Water• Electrolytes• Wastes

• Manufacture of Vitamin D

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Checkpoint 6-7: What two mechanisms are used to regulate temperature through the skin?

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Observation of the SkinObservation of the Skin

Skin attributes can indicate a serious systemic disorder

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Color

Factors that influence skin color• Amount of pigment in the epidermis

• Melanin• Carotene

• Discoloration• Blood in surface blood vessels• Oxygen in blood• Hemoglobin in blood• Other chemicals in blood

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Checkpoint 6-8: What are some pigments that impart color to the skin?

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Lesions

Any wound or local damage to tissue• Surface lesions

• Macule• Papule• Vesicle• Pustule

• Deeper lesions• Excoriation• Laceration• Ulcer• Fissure

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Checkpoint 6-9: What is a lesion?

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Burns

Categorized by • Depth of damage

• Superficial partial-thickness• Deep partial-thickness• Full-thickness

• Amount of body surface area (BSA) involved• Rule of nines• Lund and Browder method

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Tissue RepairTissue Repair

Wound healing • Occurs only in areas with actively dividing cells

• Epithelial tissues• Connective tissues• Minimally in muscle and nervous tissue

• Is affected by• Nutrition• Blood supply• Infection• Age

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Checkpoint 6-10: What two categories of tissues repair themselves most easily?

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Effects of Aging on the Effects of Aging on the Integumentary SystemIntegumentary System

Changes in• Skin• Tissues• Pigment • Hair • Sweat glands • Circulation • Fingernails and toenails

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Care of the SkinCare of the Skin

• Proper nutrition• Adequate circulation• Regular cleansing

• Removes dirt and dead skin• Sustains slightly acid environment to inhibit

bacteria• Protection from sunlight

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Skin DisordersSkin Disorders

Range from superficial to deep-seated

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Dermatitis

• Inflammation of the skin• Dermatosis is any skin disease

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Psoriasis

• Chronic, recurrent overgrowth of epidermis• Sharply outlined red (erythematous) areas• Flat areas (plaques) covered with silvery scales• A hereditary pattern sometimes present• Immune disorder may be involved

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Checkpoint 6-11: What is the difference between dermatosis and dermatitis?

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Cancer

Skin cancer is most common form of cancer in the United States• Basal cell carcinoma• Squamous cell carcinoma• Melanoma

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Checkpoint 6-12: What is the name for a cancer of the skin’s pigment-producing cells?

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Acne and Other Skin Infections

• Acne• Sebaceous glands disease

• Impetigo• Staphylococcal or streptococcal origin

• Viral infections• Herpes simplex virus• Herpes zoster virus (shingles)• Human papillomavirus (HPV) (wart or verruca)

• Fungal infections• Tinea or ringworm

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Checkpoint 6-13: What are some viruses that affect the skin?Checkpoint 6-14: What causes tinea or ringworm infections?

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Alopecia (Baldness)

Factors that affect baldness• Heredity, aging, and male sex hormones (male pattern

baldness)• Systemic disease• Drugs

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Allergy and Other Immune Disorders

Often involve the skin• Allergy—reaction to a substance• Autoimmune disorders—reaction to one’s own tissues

• Pemphigus• Lupus erythematosus• Scleroderma

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Pressure Ulcers

Pressure ulcers are skin lesions that appear where the body rests on skin that covers bony projections.

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Checkpoint 6-15: What are several autoimmune disorders that involve the skin?

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The skin, like our personalities, have various layers, which perform distinct functions—it makes each person unique, obscure, yet familiar. It identifies each individual, yet under the microscope, our skin remains HUMAN in nature.

--Martin Ponciano =)