General structure: composed of epidermis, dermis, separated by a basement membrane and a subcutaneous layer underneath Has at least 8 functions! Integumentary System- L2

Function #1: Protective barrier against 1. Loss of body fluids 2. Infection 3. Damage from physical injury 4. Heat/UV light 5. Physical stress

Function#2: Thermal regulation 1. Sweat from sweat glands 2. Controls blood supply to warm/cool body 3. insulation: barrier against outside 4. Radiation of heat (#1 way to cool body) and evaporation also a close #2

Function #3 Sensory receptors in skin react to 1. changes in temp 2. touch-pressure-pain

Function #4: Excretion of Wastes 1. Since it self-renews it can get rid of nitrogen, salt, urea

Function #5 -#8: vitamin D production energy storage (fat) fingers and toes provide a gripping surface Blood reservoir. (skin has about 8-10% of one's blood.)

First layer: Epidermis Has 5 layers of avascular stratified squamous tissue Has cells called keratinocytes and melanocytes Keratinocytes produce the protein keratin. It makes up skin surface, hair and nails Keratin helps waterproof and protect.

Second layer: Dermis (primarily connective tissue) with the following 1. Has many nerves and blood vessels going through it. 2. The cells of the dermis are primarily fibroblasts. 3. The intercellular material is largely collagen and elastin laid down in all directions by the fibroblasts. 4. Adipose cells are also common

Third Layer: Subcutaneous Layer (hypodermis) - primarily connective tissue, adipocyte cells are more predominant. This layer contains blood vessels that supply the skin.

Cells called: Melanocytes 1. Melanocytes are in the basal layer of epidermis A. Make black pigment called melanin B. this coloration protects against UV light C. Native Americans and Asians have variations of melanin to have yellowish color to skin

Melanocytes & Tanning Prolonged exposure to ultraviolet light stimulates melanocyte activity & melanin secretion in epidermis. This results in darker skin; the melanin protects the DNA of cells from UV damage by absorbing UV light. Too much exposure to UV light may overwhelm the protective function of melanin and result in sunburn.

Fingerprints Specialized structure: Dermal papillae Uneven ridges formed during fetal development NO TWO sets are exactly alike!

Hair and follicle 1. Hair - made by epidermal keratin forming cells. a. Color = various levels of melanin and carotene. Gray is due to air spaces in the hair. b. Function? c. Growth is always from base. A new hair starts and pushes the old one out. Hair goes through growth-rest stages.

Sebacious gland: usually connected to hair A. glands that secrete sebum, B. Functions to keep skin and hair soft and waterproof C. Especially active during puberty. Can clog with dead cells/sebum →pimple

Sebacious Gland, cont. D. Smooth muscle that lifts the hair is called the arrector pili. E. Nerve (sensory) F. Dermal Papillae: fingerprints. Projections extending into epidermis from dermis. Helps increase friction to help pick up things.

Sweat glands: 3000/sq. inch 1. # 1 Function- to cool the body 2. Excretes wastes 3. Regulated by nerves 4. A modified form secretes more organic materials in arm pits/pubic area. Bacteria break it down and cause odor.

Nails: -protective covers on the ends of fingers and toes -undergo keratinization

1 st degree burn Epidermis ONLY affected Redness and burning EX: sunburn

Epidermal (1 st degree) burn

2 nd degree burn Damage to both the epidermis and dermis Damage not enough to PREVENT healing

Dermal (2 nd degree) burn

Deep dermal (2 nd degree) burn

3 rd Degree burn ENTIRE epidermis, dermis, and accessory organs destroyed Tissue death

Sub-dermal (3 rd degree) burn

Skin graft

Common disorders of the Feet Athlete's Foot (right down) Skin disorders of the feet such as Callus, Athlete's foot and Plantar Warts Athlete's Foot (right down)

Tinea pedis- Athlete’s Foot

Acne

Contact dermatitis

Moles are harmless skin growths that may be flat or protruding. They vary in color from pink flesh tones to dark brown or black.

Pediculosis- lice

Decubitus ulcer (Bed sore)

Where do pressure ulcers form? Where bone causes the greatest force on the skin and tissue. For bedridden persons, most pressure ulcers form on the lower back below the waist (sacrum), the hip bone (trochanter), and heels.

Diabetic Ulcer

Pathophysiology: diabetic foot ulceration Neuropathy Sensory Loss of protective sensation Motor Abnormal foot biomechanics Autonomic Reduced skin compliance and lubrication Ulceration Infection Vascular insufficiency

Eczema

Quick Quiz: 2 pts each 1. Name 3 of the, at least 8 fx’s of integ. system 2. List and describe the 3 layers of the skin 3. Name/describe top 2 ways we lose body heat 4. Describe keratin and keratinocytes 5. Describe the relationship between skin color and melanin

Quick Quiz: cont 6. Describe what a sebacious gland is/does 7. Describe what a sweat gland is/does 8. What does Vit D have to do with skin? 9. Discuss the differences in 1 st,2 nd, 3 rd degree burns 10. Discuss two factors that can influence diabetic ulcers and pressure ulcers