Anatomy and Physiology
Chapter 6: Skin and Integumentary System
Fisher
Directions: Answer these questions in your notebook.
1. How is the epidermis formed?
Stratum basale cells divide and grow, pushing the other cells away from the
dermis toward the skin surface, the farther the cells move, the less blood supply,
and they die—keratinizing first (p. 114)
2. What is the difference between the stratum basale and the stratum corneum?
Stratum basale—deepest layer of epidermis where mitosis occurs; stratum
corneum—most superficial layer of epidermis, tough, dead, tightly packed
cells (keratinized). P. 114
3. Medicine can be injected through 3 different types of injections. Describe the
difference between each type: p.114
a. Subcutaneous injection under dermis, in subcutaneous (hypodermis)
b. Intradermal injection within skin (w/in dermis)
c. Intramuscular injection into muscle, below skin
d. Which type is also known as a hypodermic injection? Intramuscular
4. Transdermal patches are also used to administer drugs. How does the drug get
into the blood stream in this method?
Contains a small reservoir of the drug that passes through a permeable
membrane at a known rate then diffuses into the epidermis and dermis into
the blood vessels. P. 114
5. What are three uses for a transdermal patch?
Stop smoking, chest pain (due to heart disease), motion sickness p. 114
6. When cell division increases on areas of the skin that are rubbed or pressed
regularly, this causes what?
Calluses on palms and soles, corns on toes p. 114
7. Cytoplasmic extensions transfer melanin through a process called cytocrine
secretion. Describe this process.
Melanocytes(melanin production)lie in deepest portion of epidermis (stratum
basale/spinosum) but extensions of the cytoplasm pass between other cells
transferring melanin granules into these other cells p. 115
8. What factors influence skin color?
Genetics, sunlight, x-rays, blood in dermal vessels, diet, biochemical
imbalances p. 116
9. What are bedsores and how do they form?
Weight of body pressing against one area for prolonged periods (especially
where bony projections are) can cause the cells to die, and cut off the blood
supply to the area. The breakdown of the tissue can cause a pressure ulcer
(decubitus ulcer) which is a bedsore. P. 116
10. How is vitamin D related to the skin?
Can form from dehydrocholesterol made by cells in the digestive system, when
it reaches to skin and is exposed to UV from sun, it is converted to another
chemical that becomes vitamin D. p. 116
11. How do keratinocytes assist the immune system?
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Anatomy and Physiology
Chapter 6: Skin and Integumentary System
Fisher
By producing hormonelinke substances that simulate development of T
lymphocytes (WBCs) that defend against infectious bacteria and viruses. P.
116.
12. What kinds of tissues make up the dermis?
Connective, smooth muscle, epithelial, nervous p.p. 117-120
13. Describe the structure of a nail bed.
Specialized epithelial cells that are continuous with the epithelium of the skin.
P. 117
14. What is the most actively growing region of the nail?
The base of the nail plate, covered by the lunula (whitish, thickened, half-moon
shaped region) p. 117
15. How does hair form?
Epidermal cells at base of hair follicle that then grow and divide and push older
cells away toward surface becoming keratinized p. 117-118
16. What are 3 areas on the body not covered in hair?
Palms, soles, lips, nipples, and parts of external reproductive organs p. 117
17. The nails, hair, and skin all develop in what similar way?
Epidermal cells at base grow, divide, pushing older cells toward surface where
they keratinize (CH. 6)
18. Sebum is the name for what substance secreted by the skin?
Oil p. 118
19. What is the difference between apocrine and eccrine sweat glands?
Apocrine: become active at puberty and cover the axillary and groin regions
(respond to emotional upset, fright, or pain)
; eccrine: are always active and cover the forehead, neck and back (respond to
heat and physical activity) p.118-119
20. Sweat consists of what substances?
Water, salt, urea and uric acid p. 119
21. Give two examples of modified sweat glands.
Mammary glands (milk), and ceruminous glands (earwax) p. 119
22. Describe hypothermia, and the body’s attempt to maintain homeostasis.
Body T falls, muscles in walls of blood vessels contract, blood flow decreases,
sweat glands are inactive, nervous system stimulates skeletal muscle to
contract, small groups of muscles contract rhythmically (shivering) p. 120
23. Describe hyperthermia, and the body’s attempt to maintain homeostasis.
Body T rises, nerve impulses stimulate release of heat, blood carries heat to
hypothalamus in brain which signals muscles in the dermal blood vessels to
relax (vasodilation), more blood enters them and heat escapes to outside.
Eccrine sweat glands stimulated by nerves to become active and to release
sweat onto ths skin surface to evaporate, thereby carrying more heat away.
P.120
24. How does inflammation help a wound heal?
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Anatomy and Physiology
Chapter 6: Skin and Integumentary System
Fisher
Blood vessels dilate and become more permeable, forcing fluids to leave the
blood vessels and enter damaged tissues. More nutrients and oxygen are
provided, which aids healing. Inflammation causes redness, heat, swelling,
and pain. P. 120-121
25. How are the steps necessary for a wound to heal in the dermis different from
those in the epidermis?
Epithelial cells are stimulated to divide more rapidly to fill gap in epidermis. If
dermis or subcutaneous, blood vessels break, blood clots and forms scab.
Fibroblasts migrate into the region and form collagenous fibers to bind edges
together, blood vessels extend into area beneath scab, phagocytic cells remove
dead cells, and tissues are replaced. Scab sloughs off. If extensive, may leave
scar. P. 121
26. What role do phagocytic cells play in wound healing?
Get rid of dead cells and other debris p. 121
27. What is the difference between a first degree, second degree, and third degree
burn?
1st: epidermis alone (superficial partial-thickness burn
2nd: epidermis and some dermis (deep partial-thickness)
3rd: epidermis, dermis, and accessory organs (full-thickness) p. 121
28. Healing in large open wounds involves granulations, what are these?
Rounded masses consisting of new branch of a blood vessel and cluster of
collagen-secreting fibroblasts nourished by it. Often the blood vessels are
resorbed and fibroblasts migrate away leaving a scar. P. 121
29. When reading the Clinical Connection on p. 123 of the text, the stem cells
found in the patients were likely formed from what?
Dedifferentiated cells p. 123
30. What was the difference in the patients who were treated with epidermal growth
factor compared to the other patients?
Stem cells were more abundant grouped into “stem cell islands” that traversed
more than one layer; those without treatment stem cells were scattered and in
one layer at the bottom of the basement membrane. P. 123
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