Integumentary System – Notes
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more detailed information, go to www.biologyofhumanaging.com
1.
Epidermis
a.
Keratin -> barrier to microbes,
chemicals, water, trauma
1.
AGING -> (1) slightly thinner and
uneven -> ¯
barrier (chemicals);
(2) weaker and looser -> ¯
barrier (microbes, chemicals), scaly appearance
(3) slower production -> slower healing -> ¯ barrier (microbes, water, chemicals, trauma)
b.
Melanin -> barrier to light
1.
AGING -> (1) less, slower
production -> ¯ barrier to light -> sunburn, skin cancer,
wrinkling, immune response
(2) uneven distribution -> cosmetic problems ( age spots )
c.
Langerhans
cells
-> barrier (start immune responses against microbes, chemicals), fights skin
cancer
1.
AGING -> (1) decreased numbers
-> immune response -> ¯ defense (microbes, chemicals,
cancer) and ¯ allergic responses (¯ discomfort, ¯ warning of danger {microbes,
chemicals}
d.
Hair -> shade, thermal insulation,
cushion, filter, ¯
touch sensation
1.
AGING -> fewer; thinner; rougher; ¯ color; altered distribution, baldness, in hair on face, chin, lips; in eyebrows, ears, nostrils) -> most functions in most areas {some exceptions} and
altered cosmetic effect {mostly worse effect}
e.
Nails -> protect from trauma; used
as tools
1. AGING -> weaker, slower growth, less clear, rougher -> ¯ protection, worse cosmetic effect, nail infections
2.
Dermis
a.
Barrier
1.
cross-linked
collagen -> stiffness -
traumatic injury
2.
enzymes
weaken collagen ->
traumatic injury
3.
¯
fibroblast functioning -> slower healing
4.
¯
WBCs and ¯ macrophages -> ¯ immune response
5.
¯
vessels -> ¯
inflammation
6.
¯
vessels -> weaker skin and slower healing
b.
Information
1.
¯
WBCs, macrophages, mast cells -> ¯
immune response, ¯
inflammation
2.
¯
vessels -> ¯
inflammation
3.
¯
touch and pressure receptors -> ¯
sensation
c.
Temperature
regulation
1.
¯
vessels and slower vessel response -> ¯
temp. regulation (for heat & cold)
2.
¯
sweat glands and sweat gland functioning -> ¯ temp. regulation (for heat)
d.
Vitamin
D production
1.
slower
cells and reactions -> ¯
vitamin D production
2.
¯
water and fiber cross-links -> trapped
vitamin D
3.
¯
vessels -> ¯
supply of raw materials and ¯
removal of vitamin D
e.
Cosmetic
effects
1.
irregularity and binding of elastin -> sagging, wrinkling
2.
¯
water -> sagging, wrinkling
3.
¯
vessels -> paleness
4. ¯ sebum production -> roughness of skin and ¯ luster of hair
3.
Boundary between the epidermis and
the dermis
a.
¯
number of connections by keratinocytes
b.
¯
number and size of dermal papillae
c. EFFECTS = ¯ service of epidermis, separation of epidermis and dermis -> ¯ healing, ¯ pain, infection, ¯ gripping by fingerprints
4.
Subcutaneous
layer
a.
thinning
fat, ¯ water in gel -> ¯ cushioning -> injury from trauma
b. thinning fat -> ¯ insulation -> ¯ temp. regulation
5. Skin diseases
a. increased occurrence and severity with increasing age
6.
Sunlight
a.
increased
production of and damage from free radicals
b.
production of irregular keratinocytes -> skin cancer
c.
patchy distribution of melanocytes -> age spots
d.
¯
Langerhans cells ->
infection, skin cancer, warning from inflammation
e.
irregularities in elastin -> sagging and wrinkling
f.
¯
blood vessels -> ¯
inflammation for warning, ¯
temp. regulation, ¯
vitamin D production and removal
g.
thicker
capillary walls -> ¯
exchange for epidermis, dermis, vitamin D production and removal
h.
enlarged
sebaceous glands -> adverse cosmetic effects (i.e., blackheads)
i.
Prevention
1.
avoid
exposure
2.
wear
protective clothing
3.
use
sunscreen lotions
4.
use
anti-oxidant lotions
j.
Treatment
1.
Tretinoin.
(a)
reduces
sun damage
(b)
reveres
cosmetic effects from sun damage
(c)
reverses
sun damage to collagen, vessels, and the junction between the epidermis and
dermis
2.
Skin
peals and abrasion
3.
Laser
treatment
4. Moisturizers
7.
Heat
a.
production of irregular keratinocytes -> skin cancer
b.
patchy distribution of melanocytes -> age spots
c.
¯
Langerhans cells ->
infection, skin cancer, ¯ warning from inflammation
d.
¯
blood vessels -> ¯
inflammation for warning, ¯
temp. regulation, ¯
vitamin D production and removal
e.
thicker
capillary walls -> ¯
exchange for epidermis, dermis, vitamin D production and removal
f. enlarged sebaceous glands -> adverse cosmetic effects (i.e., blackheads)
8.
Decubitus
ulcers
a.
¯
immobility; age changes weaken skin; thinner fat layer; circulatory diseases
(e.g., atherosclerosis); ¯
nutrition; ¯ skin hygiene; ¯ exercise; diseases (e.g., atherosclerosis, diabetes)
b. infection; pain; adverse cosmetic effect
9.
Neoplasia
a.
benign
1.
cosmetic;
risk of skin injury; discomfort;
risk of infection
b.
malignant
1.
cosmetic;
infection; damage other organs
c.
Prevention
1. skin care; ¯ sunlight; remain active; good nutrition; regular evaluation and corrective measures; ¯ exposure to harmful factors (microbes, trauma, burns, chemicals); avoid or treat other diseases (e.g., atherosclerosis, diabetes)
© Copyright
2000 - Augustine
G. DiGiovanna - All rights reserved.
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required to purchase the book HUMAN
AGING: BIOLOGICAL PERSPECTIVES by Augustine G. DiGiovanna,
The McGraw-Hill
Companies, New York, 1994 or 2000; (2) If prior written
permission is obtained from Augustine G.
DiGiovanna, Ph.D., Salisbury University