1. Protects us from bacterial invasion and mechanical and
chemical injury
Reservoir of blood
Vitamin D synthesis
Excretion of wastes
Cutaneous sensation
Thermoregulation
2. Epidermis and dermis
3. Hypodermis
4. Stratified keratinized squamous
5. Keratinocytes/melanocytes/Langerhans cells/Merkel's cells
6. a. Keratinocytes
b. Keratinocytes
c. Langerhans cell
d. Melanocytes
e. Keratinocytes
f. Merkel's cells
g. Melanocytes
7. Blister
8. Callus
9. Corneum/lucidum/granulosum/spinosum/basale.
10. a. Papillary layer j. S. lucidum
b. S. basale
k. S. basale
c. S. corneum
l. S. granulosum
d. S. basale
m. S. granulosum
e. S. spinosum
n. Papillary layer
f. S. corneum
o. Papillary layer
g. S. spinosum
p. Reticular layer
h. Reticular layer
i. S. lucidum
11. Nails/hair/sweat glands/sebaceous glands
12. Shading/protection/filtering.
13. Shaft/root
14. Cuticle/Cortex/Medulla
15. a. Hair bulb
b. Papillae
c. Root
d. Shaft
e. Hair follicle
f. Arrector pili
16. Nail
17. Sudoriferous glands
18. Lips/nipples/genitals
19. Eccrine/Apocrine
20. Water/salt/urea/ammonia/uric acid/lactic acid/Vitamin C/Etc.
21. a. Eccrine
h. Apocrine
b. Eccrine
i. Apocrine
c. Apocrine and holocrine j. Holocrine
d. Holocrine
k. Eccrine
e. Apocrine
l. Holocrine
f. Holocrine
m. Holocrine
g. Eccrine
n. Holocrine
22. Melanin/Carotenes/Hemoglobin
23. Melanin
24. Melanocytes/keratinocytes
25. Depresses immune cells/Clumps elastic and collagen fibers/destroys
keratinocytes in S. basale/etc.
26. a. Melanin
b. Hemoglobin
c. Carotene
d. Carotene
e. Carotene
27. A callus is caused by excessive, but gradual friction on the skin's
surface. Keratinocytes in the stratum basale are stimulated to divide
more rapidly than usual and over a period of days thicken the stratum corneum
resulting in a thicker skin region called a callus.
28. A blister is caused by excessive and rapid friction on the skin's
surface that results in the separation of the epidermis from the dermis
below. As the two layers separate, fluids from the dermis leak into
the weakened area creating the typical raised area.
29. A tan is caused by excessive exposure to the sun (or UV radiation
from a variety of sources). The UV radiation stimulates melanocytes
to make more melanin which is transferred to keratinocytes as they move
upward through the epidermal strata. Keratinocytes with more melanin
filter UV radiation better than those keratinocytes with less melanin.
Since melanin is a dark pigment, the skin becomes dark resulting in a tan.
30. Melanocytes manufacture melanin and move the substance into the
tips of their cellular extensions. Keratinocytes phagocytize the
melanin-rich tips of these extensions. Increased exposure to UV radiation
stimulates melanin production which results in the darkening of the skin,
or tan.
31. No. Dark-skinned races have similar numbers of melanocytes,
but each melanocyte produces more melanin than a melanocyte of light-skinned
races.
32. A pimple occurs when the exit point, usually at the shaft of a
hair, for sebum from a sebaceous gland is blocked by dirt and other debri.
The sebum cannot escape and accumulates beneath the skin causing the redness,
swelling, and pain.
33. Body odor is caused by bacterial breakdown of the protein component
of sweat as well as the unique combination of organic molecules released
in sweat. Each person has their own unique smell which in some societies
is considered important in attracting a mate.