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Chp. 5-B2
The Integumentary System
I. Outside covering of a body
A. Direct contact with outside environment
B. Subject to continual abuse
1.
2. wind, sun, etc.
3.
C. Skin is resilient, versatile & repairs quickly
II. Structure of the skin (cutaneous membrane)
A. Three layers
1.
2. DERMIS-inner layer
3. SUBCUTANEOUS-anchors dermis to body
B. EPIDERMIS
1.
a. no blood
b. nutrients by diffusion
c. near basement membrane
-division of cells (mitosis)
2. new cells push up to surface
a
-keratin added (prevents water loss)
b. columnar to squamous
c. columnar cells
-mitosis
(clinical applications p. 76 malignant melanoma’s)
d. mitotic divisions decrease as cells move upward
e. outer layer 20/30 layers of squamous cells
3.
C. DERMIS p. 76
1. dense connective tissue & thicker than epidermis
2.
3. contains collagen & elastic fibers
a. strength
b.
4. if skin is overstretcheda. dermis damaged
b. stretch marks (scars)
5. creates framework for blood vessels & nerves
6.
a
b. cold
2
c. pain
d. pressure
e. Touch
7. other mammals-this is used to make leather
8.
a. upper layer
-forms unique ridge (foot,fingerprint)
b. lower layer
-deeper tissue
-provides strength & resilience for stretching
9. Blisters
a. fluid-filled pocket between epidermis and dermis
b.
-plasma from blood escapes vessels & goes to the area
D.
1. not part of skin
2.
3. contains adipose tissue & connective tissue
4. Adipose tissue
a. provides cushion to organs
b. provides heat
c.
III. Skin color
A. Color determination
1.
2. physiological
3. environmental
4.
a. everyone has the same number of melanocytes (yellow, brown,
black)
b. Albinism-lack of melanin
B.
1. carotene pigment
a. some people
b. yellow tint
2.
a. due to blood vessels dilating & constricting
IV. Epidermal derivatives (accessory structures)
A.
1. found everywhere buta. palms of the hand
b.
c. lips
3
d. genitalia
2. Anatomy of hair p. 78
a.
-extends beyond epidermis
-no nerves or blood
-cuticle made of keratin
-shape of shaft determines if hair is straight, wavy, or curly
b. root
-enclosed in hair follicle
-color determined by type of melanin
-aging-melanocytes less active & replaced with air bubbles to
form gray/white
c.
-when contracts
B. Nails p. 79
1. Anatomy
a. dead epidermal cells
b.
c. free edge
d. nail body
e.
2. Growth (physiology)
a. as they grow, they become keratinized & move over the nail bed
b.
C. Glands (sweat, oil and tear)
1. SEBACEOUS glands (oil)
a.
b. sebum=oily secretion
c. transported by a duct (exocrine) to the hair shaft
d.
-keeps hair & skin soft
-prevents water loss
-acne/sebum blocks follicle & forms a blackhead and then
pimple
2.
a. found almost everywhere on body
b. more on palms & soles
c.
-water & salts removed
-persperation a nerve response to heat and nerves
4
d. larger sweat glands (underarms & genitalia)
-water/salts/fatty acids & proteins
-stimulated during pain, stress & sexual arousal
-bacteria break it down to cause the body odor
3.
a. secrete cerumen
b. repels insects
c.
V. Functions of the skin
A.
1. keratin (water proof)
2.
a. acidic & inhibit bacterial growth
3.
4. Protects from mechanical, chemical, & thermal injury
B.
C. Regulation of body temperature (negative Feedback for homeostasis)
1. ATP
a.
b. 60% used to create heat
2.
a. constriction
b. dilation of blood vessels
D.
1. required for Ca & Ph absorption in small intestine
a. essential for bone formation
b.
2. skin can take UV light & make Vit D.
ONLY NEED A SMALL AMOUNT OF LIGHT
VI. Burns
A.
B. Electrolyte & Protein loss
1. leads to osmotic imbalance
2.
3. circulatory shock
C. Bacterial infections/fungi & other pathogens
1.
2. low immunity/fails after 2-3 days
3. High moisture to area
D.
E. Rule of 9’s
a. method used to determine burn coverage
b
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READ FOCUS ON AGING pg. 82 and look at pg. 83