C H A P T E R 11 Anatomy and Physiology of the Human Body

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved The Integumentary System 4 4 U N I T

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Functions of the Skin Protection  Against invasion by bacteria  Underlying tissue from injury  Against loss of body fluid Perception  Works with the nervous system to provide a sense of touch  Registers pain, heat, cold, and pressure (continued)

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Functions of the Skin Absorption  Skin can absorb moisture and medication as well as some vital vitamins and minerals through the hair follicles and glands. Excretion  Skin eliminates water, salt, and waste. (continued)

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Functions of the Skin Temperature control  When the temperature control center in the brain senses that the body is too warm, blood vessels dilate so that heat escapes through the skin surface.  When it is cold, the vessels constrict to prevent heat loss from the skin surface.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Structures of the Skin In 1 square centimeter of skin, there are:  3 million cells  24 sensory apparatuses for heat and cold  200 nerve endings  25 pressure apparatuses  4 yards of nerves  3,000 sensory cells  700 sweat glands  1 yard of blood vessels  15 sebaceous glands

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved How the Body Cools Its Surface The skin contains sweat glands that produces moisture when the body is too hot. This moisture evaporates from the skin surface to provide a cooling effect.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved The Three Layers of Skin Tissue 1. Epidermis  Top layer 2. Dermis  Middle layer  Filled with fat, blood vessels, sweat and oil glands, and nerves 3. Subcutaneous  Inner layer  Contains blood vessels, nerves, and hair follicles

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Appendages of the Skin 1. Sweat glands  Produce moisture to cool the skin surface 2. Oils glands  Produce oils to prevent hair and skin from becoming dry and brittle 3. Hair 4. Nails

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Diseases and Disorders

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved The Process That Causes Wrinkles With age, the elastic fiber in the dermis increases in size, and collagen in the dermis degenerates. The support for the epidermis is decreased and wrinkles develop.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved What Causes a Suntan to Develop When the skin is exposed to the sun, it may become reddened because of superficial blood vessel dilation. The melanin pigment increases and moves to the surface to protect the underlying tissue. A brownish coloration or suntan appears.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Basal Cell Carcinoma Slow-growing, locally destructive skin tumor; also called skin cancer Usually occurs in areas where there are abundant sebaceous follicles More common in persons over 40, especially those who are blond and fair skinned

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Squamous Cell Carcinoma Invasive tumor that has metastatic potential Usually occurs in Caucasian men over the age of 60 Working outdoors and smoking increases the risk for developing this cancer.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Ordinary Moles versus Melanoma Shape Border Color Diameter Development

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Factors that Contribute to the Development of Melanoma Intense exposure to ultraviolet (UV) rays from sunlight Blond or red hair Fair skin with tendency to sunburn Blue eyes

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Blushing The skin has a rich supply of blood vessels. When we blush, the vessels dilate and cause reddening of the skin.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Birthmarks and Moles Birthmarks can be caused by coloration from a collection of blood vessels or from patches of skin pigment. Moles are pigmented patches of skin.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Albinisim Persons who have little or no skin pigment to give it color are identified as albinos. The hair is pale yellow or white. The eyes appear red and are very sensitive to light.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Alopecia Loss of hair that usually occurs in the scalp Physiologic alopecia  Temporary hair loss Alopecia areata  Limited to small patches of hair loss Male pattern baldness  Most common form of hair loss  Affects men over age 30

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Cellulitis Acute diffuse or spreading inflammation of the skin and subcutaneous tissue Causes localized swelling, pain, heat, and redness Usually the result of a streptococcus or Staphylococcus infection

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Eczema Acute or chronic skin disorder that results in dry, red, itchy, and scaly skin Eczema can be irritated by diet, cosmetics, clothing, medications, soaps, and environmental elements, as well as emotional stress.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Dermatitis and Folliculitis Dermatitis  Inflammation of the skin  Can refer to any form of skin condition such as seborrhea, eczema, contact dermatitis, exfoliative dermatitis, or stasis Folliculitis  Infection of the hair follicle with the formation of a pustule

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Furuncles and Carbuncles Furuncles  Hard, painful nodules that develop over time and then rupture and release pus and dead cells through a drainage point  May develop from folliculitis Carbuncles  Began as a nodule, then enlarge and have multiple drainage points

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Herpes Viral infection that causes groups of small, painful, clear vesicles Type I: Lesions appear in the mouth and nasal area. Type II: Lesions appear in the genitals.

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Herpes Zoster Also called shingles Acute infectious process from the same virus that causes chickenpox Results in fever, malaise, and usually unilateral eruption of vesicles on the back, chest, or neck

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Hirsutism and Impetigo Hirsutism  Excessive development of body hair that could be hereditary or the result of an endocrine system disorder Impetigo  Contagious skin infection with macules and vesicles that erupt and form a characteristic yellow crust

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Keloids and Lyme Disease Keloids  Scars that develop excess dense tissue as they heal Lyme disease  Tick-borne disease that is generally the result of a spirochete-infested deer tick

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Pediculosis The infestation of parasitic lice Pediculosis capitis  Head lice Pediculosis corpus  Body lice Pediculosis pubis  Lice attached to pubic hair; commonly called crabs

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Poison Ivy and Psoriasis Poison ivy  Dermatitis that results from contact with the poison ivy plant Psoriasis  Chronic inflammatory skin condition that causes red papules covered with silvery scales

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Rosacea and Ringworm Rosacea  Chronic skin eruption that makes the face, especially the nose and cheeks, look flushed Ringworm  Fungal infection that causes flat lesions that may be dry and scaly or moist and crusty

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Scabies and Urticaria Scabies  Skin infection caused by a skin mite; results in intense itching Urticaria  Also called hives; a self-limiting reaction to allergens that results in distinct wheals surrounded by reddened areas

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Verrucae Also called warts; a benign viral infection of the skin that results in rough, elevated, rounded areas on the skin surfaces

Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Unit Summary Which layer of skin contains blood vessels, nerves, hair follicles, sweat, and oil glands? Describe the differences between an ordinary mole and melanoma. What is a temporary red, itchy spot caused by an allergic reaction or an insect bite called?