Chapter 5
The Integumentary System:
•
Protects; Sensation; Vit. D; Temp regulatn; excretn
A. Skin
1. Epidermis
 Roof
 Stratified squamous
A. Stratum basale:
 Bottom
 Mitosis ~ every 19 days

1 surfaces ~ 40-56 days later
B.
Stratum Granulosum:
 Fill w/hard protein keratin (die)
C.
Stratum Corneum
 Upper
 Protective: cells coated w/lipid
 Top sloughs
 Callus: friction ↑ cell layers
 Corn: thickened area over bone
2. Dermis
 House
 Collagen (strength)
 Cleavage Lines (fiber orientation)
 resist stretching
 parallel incision heal best
 striae: stretch marks
Skin Cont.


Few fat cells/macrophages
Dermal papillae (upper)
 Blood vessels (move matl’s, temp reg)
 Shape finger/ft print
 Grip of hand/ft
B. Skin Color
1.
Melanin:
 Brn/blk pigment molecule
 UV protection
 Melanocytes:





Produce melanin vesicles: melanosomes
Vesicles phagocytized by epidermal cells
Freckles/moles: most
Palms/soles: least
# of melanocytes:
 Same for all races
- Skin cells

Production based on:
 Genetics: races
 Albinism = recessive (no melanin)
 Hormones: pregnancy mask
 UV light: suntan
2.
Tattoo: bluish hue: dermal fibers scatter light
3.
Cyanosis: bluish hue: ↓ bld O2
Irregular heart w/
Undersized lungs
Cyanosis of nail beds with extreme
pulmonary dysfunction
4.
5.
Carotene: yellowish lipid-soluble pigment (carrots)
Jaundice: yellow w/liver damage - bile in bld
Jaundice: Yellow skin discoloration caused by hyperbilirubinemia
Anatomy of the liver. An obstruction in the bile
duct may lead to jaundice.
6.
Birthmark: congenital disorder of dermal BV
Capillary Malformation
("Port-wine Stain")
Most birthmarks are no risk to health
Vascular birthmarks are caused by enlarged small blood vessels just
beneath the skin's surface. The most common are known as "angel's
kisses“when located on the forehead or eyelids, and as "stork bites"
when they appear on the back of the neck.
C. Hypodermis




Foundation
Subcutaneous (under skin)
½ body fat (insulate/pad); TBF count
Injection site
D. Accessory Skin Structures
1.
Hair:
A.
B.
Shaft (visible)
Hair root (bulb) in follicle
 Dermal papilla nourishes
 Divide/keratinize
The cuticle, or outer layer,
of a healthy shaft of hair
A split end, caused when
a hair shaft is pulled apart
 Phases
 Growth:
lash-30 dys/scalp-3 yrs
 Rest: lash 105 dys/scalp-1-2 yrs
C.
Pattern baldness: sex linked (hormone)
D.
Color: determined by bulb melanocytes
 Age: gray -↓ activity; white - no actvty
How does hair turn gray? The melanocytes in hair stop producing melanins!
2. Muscles: arrector pili (smooth)
A. Gooseflesh: hair perpendicular
B. W/fur: insulate/fierceness
3. Glands:
Sebaceous- sebum (oil) to follicle
B. Eccrine- sweat (↑ H2O) to skin
C. Apocrine- org-sweat to genital/axillary follicle
 Active w/puberty – bacterial decay=odor
A.
An apocrine gland, which
produces little sweat but is
responsible for the body's
natural 'scent'.
E. Physiology


Temp reg (dermal BV); excretion (urea-sweat)
Vitamin D prodctn: in skin w/UV

Stimulates Ca/P uptake SI= muscle/bone health
F. Diagnostic

Burns: degree of depth

Partial-thickness: part of basale viable
(regenerate from edges, follicles)
 1°: epidermis – edema, no scar
 2°: epi/dermis-blister, may scar
The epidermis, the outer layer, is burned.
Reddening occurs and swelling is possible.
The epidermis is burned through, and the dermis,
is also injured. An intense red discoloring is
accompanied by severe pain, swelling and blisters.

Full-thickness:

3°: epi/dermis destroyed-skin graft
All layers of skin are burned through to the fat, muscles and possibly
to the bone. There may be severe pain, but sometimes extensive
nerve damage results in little or no pain.
First Degree Burn
Superficial
(epidermal burn)
Third Degree Burn
Deep
(sub-dermal burn)
Second Degree Burn
Intermediate
(superficial dermal burn)
Fourth degree burn

Skin Cancer:

most common type of cancer; UV exposure

Basal cell carcinoma: common; open ulcer; treatable
Massive Ulcerating
Basal Cell Carcinoma
Histology:
basal cell
carcinoma,
high power

Squamous cell carc. : keratinized tumor;↓ metastasis

Malignant melanoma: rare; melanocytes-mole:
metastasis common (fatal)
Aging


↓ skin activity & functn
Age spots w/↑ # of melanocytes (some areas)