Unit 4: Study Guide Essay

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Unit 4 Lecture Study Guide
Use the lecture folder to help you complete this guide. The more detail you can provide the better prepared for the test you will be.
1. What is the integumentary system and its primary characteristics?
The integumentary system is composed of the skin, hair, nails sweat and oil glands.
Covers the entire body, accounts for about 7% of total body fat, pliable yet durable, composed of the dermis and epidermis, and it’s thick.
2. Describe and give at least one example of each of the functions of the integumentary system.
Skin secretions
Physical/mechanical barriers
Biological barriers
Body Temperature Regulation
Production of copious amounts of sweat to dissipate heat
Constriction of dermal blood vessels to retain heat
Cutaneous Sensation- Cutaneous sensory receptors (nervous system)
Meissner’s corpuscle and Merkel cells- detect changes in pressure
Pacinian receptors- detect deep pressure contacts Hair follicle receptors- movement across the surface of the skin
Nerve endings- detect painful stimuli
Metabolic Functions
Synthesis of Vitamin D- increases calcium absorption in the body
Chemical conversions of many substances
Blood Reservoir- vasoconstriction and vasodilation
Excretion- elimination of nitrogen- containing wastes, salt and water
3. Differentiate between chemical, physical/mechanical and biological barriers provided by the integumentary system. Be sure to provide a minimum of one example for each.
Chemical barriers
Skin secretions
Low pH and sebum slow bacterial growth on skin surface
Human defensin- natural antibiotic
Cathelicidins- proteins that prevent Strep A infection in wounded skin
Melanin- chemical pigment that prevents UV damage
Physical/mechanical barriers- continuity of the skin and hardness of keratinized cells
Continuity prevents bacterial infection
Glycolipids prevent diffusion of water and water-soluble substances between cells
Substances that are able to penetrate the skin:
Lipid- soluble substances (i.e., oxygen, carbon dioxide, steroids, and fat-soluble vitamins)
Oleoresins of certain plants (ex. Poison ivy and poison oak)
Organic Solvents (ex. Acetone, dry cleaning fluid, and paint thinner)
Salts of heavy material (ex. Lead, mercury, nickel)
Penetration enhancers
Biological Barriers- Langerhans’ cells, macrophages, and DNA
Langerhans’ cells in epidermis present antigens to lymphocytes
Dermal macrophages (2nd line of defense)- attack bacteria and viruses that have penetrated the epidermis
DNA structure- the electrons in DNA absorbs UV radiation and converts it to heat
4. Create a chart that helps you differentiate the epidermis and dermis. Be sure to include things such as cell composition, cell populations and layers.
Epidermis Dermis

Composed of epithelial tissue
Cell population:
Langerhans’ cells
Merkel cells
Divided into 5 distinct layers
Stratum basale- deepest layer
Stratum spinosum
Stratum granulosum
Stratum lucidum- (thick skin only)
Stratum corneum- outermost layer
5. Order the layers of the epidermis from outermost to deepest.
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
6. What contributes to skin color?
7. List the appendages of the skin and what purpose they serve.
Nails- hardened nails protect the delicate tissues of the fingers and toes
Hair follicles and hair- to regulate heat, also works as a sensory item
Sweat glands- secrete sweat, body odor, wax, or milk
Sebaceous (oil )glands- important in inhibiting microbial growth on the surface of the skin, waterproofs the hair and the skin
8. Differentiate between first, second and third degree burns.
First degree burns- only the epidermis is damaged
Second degree burn- the epidermis and the upper dermis is damaged
Third degree burn- the entire surface of the skin is damaged
9. Describe the main types of skin cancer.
Basal cell carcinoma- most