Memmler’s The Human Body in Health and Disease 11th edition Chapter 6 The Skin in Health and Disease

The Integumentary System Skin and associated structures form integumentary system

Structure of the Skin Skin consists of two layers Epidermis Strata Blood vessels, nerve endings, and glands

Cross section of the skin.

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

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

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?

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

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

Question: In what layer of the skin do you find the sebaceous glands? a. dermis b. stratum corneum c. subcutaneous

Answer: a. dermis

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

Sebaceous (Oil) Glands Produce a variety of secretions Sebum Vernix caseosa Eye lubrication

Sudoriferous (Sweat) Glands Located in the dermis and subcutaneous tissue Eccrine type sweat glands Apocrine sweat glands Ceruminous glands Ciliary glands Mammary glands

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?

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

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?

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

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

Nail structure.

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

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

Protection Against Dehydration Skin prevents water loss by evaporation Keratin in the epidermis Sebum release from the sebaceous glands

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

Collection of Sensory Information Skin has many nerve endings and other special receptors Free nerve endings Touch receptors (Meissner corpuscle) Deep pressure receptors (Pacinian corpuscle)

Other Activities of the Skin Absorption of substances such as medications Excretion Water Electrolytes Wastes Manufacture of vitamin D

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

Question: True or False?: Gas exchange is a function of the skin.

Answer: False: No, gas exchange is not a function of the skin; the skin does not “breathe.”

Observation of the Skin Skin attributes can indicate a serious systemic disorder

Color Factors that influence skin color Amount of pigment in the epidermis Melanin Carotene Discoloration Pallor: pale skin, reduced blood flow Flushing: redness, as in fever Cyanosis: bluish color of skin; lack of oxygen in blood Yellow skin: jaundice, bilirubin in blood; carotenemia from excessive intake of carrots or other deeply colored vegetables

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

Lesions Any wound or local damage to tissue Surface lesions Macule Papule Vesicle Pustule Deeper lesions Excoriation Laceration Ulcer Fissure

Checkpoint 6-9: What is a lesion?

Question: A crack in the skin is called a____. a. macule b. fissure c Question: A crack in the skin is called a____. a. macule b. fissure c. ulcer

Answer: b. fissure

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

Question: What is the Rule of Nines used for. a Question: What is the Rule of Nines used for? a. to measure the severity of acne b. to determine the depth of decubitus ulcers c. to calculate the percentage of body surface area affected by a burn

Answer: c. to calculate the percentage of body surface area affected by a burn

Tissue 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

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

Effects of Aging on the Integumentary System Changes in Skin Tissues Pigment Hair Sweat glands Circulation Fingernails and toenails

Care of the Skin Proper nutrition Adequate circulation Regular cleansing Removes dirt and dead skin Sustains slightly acid environment to inhibit bacteria Protection from sunlight Exposure to UV light causes genetic mutations in skin that can lead to cancer, and causes premature aging.

Skin Disorders Range from superficial to deep-seated

Dermatitis Inflammation of the skin Dermatosis is any skin disease Atopic dermatitis

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

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

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

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

Acne and Other Skin Infections 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

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

Question: Acne is a disease of what component of the integumentary system? a. sebaceous glands b. hair follicles c. epidermis

Answer: a. sebaceous glands

Alopecia (Baldness) Factors that affect baldness Heredity, aging, and male sex hormones (male pattern baldness) Systemic disease Drugs

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

Pressure Ulcers Skin lesions that appear where the body rests on skin that covers bony projections. Also known as decubitus ulcers or bedsores

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

End of Presentation