1. Chapter 5
INTEGUMENTARY SYSTEM

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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
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FUNCTIONS OF THE SKIN
Temporarily stores fat, glucose, water, and salts
Screens out ultraviolet radiation
Absorbs certain drugs and chemical substances
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4. 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

5. 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.
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6. 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
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STRUCTURE OF THE SKIN
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8. 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

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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
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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
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11. 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
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12. REPRESENTATIVE DISORDERS OF THE SKIN
Acne vulgaris
Athlete’s foot
Dermatitis
Eczema
Impetigo
Psoriasis
Ringworm
Urticaria (hives)
Boils
Herpes
Genital herpes
Shingles (herpes zoster)
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13. 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

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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
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15. 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

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SKIN LESIONS
Pressure Ulcers (Decubitus) are the result of constant pressure against an area of tissue that lies over a bone
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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
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