Chapter 5 INTEGUMENTARY SYSTEM

©2004 Delmar Learning, a Division of Thomson Learning, Inc. FUNCTIONS OF THE SKIN The skin has 7 functions: Covers underlying tissues to protect against dehydration, injury, and germ invasion Regulates body temperature Helps manufacture vitamin D Serves as the site of many nerve endings ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

©2004 Delmar Learning, a Division of Thomson Learning, Inc. FUNCTIONS OF THE SKIN Temporarily stores fat, glucose, water, and salts Screens out ultraviolet radiation Absorbs certain drugs and chemical substances ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

Layers of the Skin Epidermis Epidermis - the outermost covering of epithelial cells with no blood vessels Surface layer (stratum corneum) consists of dead cells rich in keratin Keratin- protein that provides a waterproof covering to prevent water loss Also contains melanocytes Make the protein melanin that protects against the uv rays of the sun

Layers of the Skin Dermis Thicker inner layer of the skin Contains masses of connective tissue, blood vessels, nerve endings, muscles, hair follicles, oil and sweat glands, and fat cells Sensory nerves located here are sensitive to pain, heat, cold, pressure, and touch Blood vessels in the dermis aid in regulation of body temperature to maintain homeostasis When external temperatures increase or decrease blood vessels dilate to bring more warmed blood flow to the surface of the body from deeper tissues. ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

Layers of the Skin Subcutaneous Subcutaneous (hypodermal layer) lies under the dermis and consists of loose connective tissue Contains about one-half the body’s stored fat Attaches the Integumentary system to surface muscles ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

©2004 Delmar Learning, a Division of Thomson Learning, Inc. STRUCTURE OF THE SKIN ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

APPENDAGES OF THE SKIN Hair Composed of a root shaft, outer cuticle layer, cortex, and medulla Cuticle layer consists of nonliving cells Root- part of the hair that is implanted in the skin Contains genetic disorder alopecia- baldness Hair follicles are attached to muscle When the arrector pili muscle is stimulated this is what causes hair to stand up and goosebumps

©2004 Delmar Learning, a Division of Thomson Learning, Inc. Appendages of the Skin Nails Hard structures found on fingers and toes Formed in the nail bed or matrix The elongated cells fuse together to form hard keratinized plates As long as a nail bed remains in tact a new nail can be formed ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

©2004 Delmar Learning, a Division of Thomson Learning, Inc. Appendages of the Skin Sweat Glands Perspiration is 99% water with a small amount of salt and organic materials Also known as sudoriferous glands are distributed over the entire skin surface Large numbers found under the arms, palms of the hands, soles of the feet, and forehead These glands are activated by heat, pain, fever and nervousness Sebaceous Glands Secretes sebum (oil) that lubricates the skin keeping it soft and pliable ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

THE INTEGUMENT AND ITS RELATIONSHIP TO MICROORGANISMS Most skin bacteria are associated with hair follicles or sweat glands where nutrients and moisture are present The best way to prevent disease is by washing the hands Handwashing should take 30 seconds ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

REPRESENTATIVE DISORDERS OF THE SKIN Acne vulgaris Athlete’s foot Dermatitis Eczema Impetigo Psoriasis Ringworm Urticaria (hives) Boils Herpes Genital herpes Shingles (herpes zoster) ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

SKIN CANCER Basal cell carcinoma is the most common and least malignant skin cancer usually occurring on the face May be treated by cryosurgery Squamous cell carcinoma occurs in the epidermis and grows rapidly. Occurs most often on the scalp and lower lip Can be treated by surgical removal or radiation Malignant melanoma is present in pigmented cells called melanocytes Usually appears as a black or brown irregular patch that occurs suddenly Treated with surgical removal and chemotherapy

©2004 Delmar Learning, a Division of Thomson Learning, Inc. BURNS Burns are the result of radiation from sun, heat, boiling water, steam, fire, chemicals, and electricity Usually referred to as first, second, and third degree depending on the skin layers affected ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

BURNS Classification of burns First degree burns Epidermis is damaged Symptoms are redness, swelling, and pain Treatment: application of cold water, burn heals in about a week Second degree burns epidermis and dermis are damaged Symptoms include pain, swelling, redness, and blistering Treatment includes medication and sterile dressings Third degree burns destruction of epidermis, dermis, and subcutaneous Symptoms include loss of skin, blackened skin, but possibly no pain, blood loss Treatment includes prevention of infection, fluid replacement, and a skin graft

©2004 Delmar Learning, a Division of Thomson Learning, Inc. SKIN LESIONS Pressure Ulcers (Decubitus) are the result of constant pressure against an area of tissue that lies over a bone ©2004 Delmar Learning, a Division of Thomson Learning, Inc.

©2004 Delmar Learning, a Division of Thomson Learning, Inc. SKIN LESIONS 4 Stages of pressure ulcers are: Stage I - skin is red but unbroken Stage II - blisters; broken or unbroken Stage III - all layers of skin are broken Stage IV - ulcerated area involves underlying muscles, tendons, and bones ©2004 Delmar Learning, a Division of Thomson Learning, Inc.