Review for Chapter 6: Integumentary System
Name______12-06-16 Hour_____ Desk#_____
1. Define tissue (oops meant to put organ).
Two or more tissues working together to perform a specialized function
2. What is the largest organ in the body by weight?
skin
3. Describe at least 4 functions of skin.
o Protection from germs and chemicals from the outside environment
o Retards water loss and helps regulate body temp.
o Houses sensory receptors
o Contains immune system cells
4. List and describe the layers of the epidermis:
o Cells of stratum basale divide & grow quickly; they are well nourished
o stratum spinosum
o stratum germinativum or germinosum
o stratum corneum outermost layer made of keratinized dead cells
5. Distinguish between the epidermis and dermis.
Epidermis=lacks blood vessels; outer layer of skin; cells contain melanin from melanocytes; stratified squamous cells
Dermis=has blood vessels that nourish surrounding tissue including lowest layer of epidermis; inner layer of skin; irregular, dense connective tissue
6. Explain the functions of the subcutaneous layer.
made of loose connective tissues & adipose; Important in the regulation of temperature of the skin and rest of body; Anchors the other layers of the skin to the muscles beneath the skin and also functions to protect the muscles and bones whenever we fall or hit our bodies on something.
7. Explain what happens to epidermal cells as they undergo keratinization.
New cells enlarge & push old epithelial cells away from the dermis toward the surface of the skin. The farther cells travel, the poorer their nutrient supply becomes & eventually they die (largely made of keratin)
8. Describe the function of melanocytes.
Melanocytes are specialized cells in the epidermis that produce the dark pigment melanin.
9. Discuss the functions of melanin.
Melanin provides skin color & absorbs UV radiation preventing DNA mutations.
10. Name the tissue(s) of the dermis. Mostly made of irregular dense connective tissue including tough collagenous fibers & elastic fibers in a gel-like ground substance giving skin toughness & elasticity
11. Describe how nails are formed. (answer on next page)
Nails start in the nail root, hidden under the cuticle. When cells at the root of the nail grow, the new nail cells push out the old nail cells. These old cells flatten and harden, thanks to keratin, a protein made by these cells. The newly formed nail then slides along the nail bed, the flat surface under your nails.
12. Distinguish between hair and a hair follicle.
A hair folicle is the root of the hair which is located in the lower part of the dermis. It is also connected to the arrector pili muscle. Hair is better known as the hair shaft and is the part inside of the hair folicle that comes out through the very top layer of skin.
13. How is hair color determined?
Hair color is determined by genes that give signals for the amount of melanin to be produced. The more melanin, the darker the hair color.
14. Explain the function of sebaceous glands and how it relates to acne.
Sebaceous glands that are overactive or inflamed can produce acne.
15. Explain the importance of body temperature regulation.
Maintaining a stable body temperature means the amount of body heat the body loses is balanced by the amount it produces (homeostasis).
B. As body temperature rises (such as from exercise), nerve impulses stimulate structures in skin to release heat
16. Describe the role of the skin in promoting the loss of excess body heat.
When the body builds up excess heat, blood vessesl dialate (enlarge) releasing heat energy; when cold, vessels constrict to conserve heat; When body temp. falls, sweat glands become inactive; if the temp. continues to fall, small groups of muscles contract slightly to produce shivering
17. Distinguish between the healing of shallow and deeper breaks in the skin.
1. If a break in skin is shallow, epithelial cells stimulate to divide more rapidly
2. If a cut extends into dermis or subcutaneous layer, blood vessels break & blood forms a clot (a scab is a blood clot & dried fluids)
3. Fibroblasts form new fibers that bind edges of wound together; cells divide & replace damaged tissues; then phagocytes remove dead cells
4. A scar results if the wound is extensive
18. Distinguish between first, second, & third-degree burns.
1. 1st degree burns only effect the epidermis
2. 2nd degree burns affect the dermis & epidermis; blisters form
3. 3rd degree burn affects entire thickness of skin & skin becomes dry and leathery; if extensive, a skin graft may be needed
4. To estimate the extent of area burned, physicians use"rule of nines" (skin's surface divided into 11 areas of 9% each)
19. Discuss 3 effects of aging on skin.
A. Aging skin affects appearance, temp. regulation, & vitamin D production
B. Synthesis of collagen & elastin slows
C. Skin becomes drier because sebaceous glands produce less oil (B & C contribute to wrinkles from aging); more opaque
D. Slowed melanin production causes gray or white hair
E. Nail & hair growth is impaired, pain & pressure sensitivity diminishes, &
less able to tolerate heat
20. Using the rule of 9’s, estimate the extent of damage for an individual whose body, wearing only a short nightgown, was burned as she was leaving a burning room. What special problems might result from the loss of the individual’s functional skin surface? How might this individual’s environment be modified to compensate partially for such a loss?
About 50% of the body has been burned which can cause reduced ability of the skin to fight off infections, regulate temperature, loss of nerve structures & sensory receptors, etc…
21. Explain why skin may peel after getting a severe sunburn.
Damage skin is expelled in order to rid the body of cells in which DNA has mutated which can help avoid pre-cancerous and cancerous conditions of the skin.