Notes: The Integumentary System
Skin and Body Membranes:
I. Functions:
i.
ii.
iii.
II. Epithelial vs. Connective Membranes
EPITHELIAL
CONNECTIVE
INCLUDES:
DESCRIPTION OF SPECIFIC
MEMBRANES:
Components of the Integumentary System:
1. SKIN
2. SKIN DERIVATIVES =
Integument functions
I. Protection
A. biological (cells)
macrophages(dermis) & Langerhan's cells (epidermis) engulf invaders
B. mechanical (physical)
1. continuity - special junctions (tight & desmosomes) form impermeable sheet
2. keratin - blocks diffusion of water & water soluble substances
C. chemical
1. skin secretions (acid mantle): tears, sweats & oils lower pH and also contain
lysozyme
2. melanin - pigment shield
II. Excretion - limited amounts of _________________ containing wastes and sodium chloride
III. Homeostasis of body temp.
A. Heat production - chief determinant - ________________________________
B. Heat loss/gain
1. 80% of heat transfer occurs through skin - rest through mucosa
2. regulated by regulating blood flow to skin (vasoconstriction/vasodilation)
IV. Vitamin D production - imp. in _____________ uptake from stomach into blood
_________________ molecules - when exposed to UV light become inactive vitamin D
(precursor) - precursor is modified into active vitamin D in _________________
V. Sensation
Skin Structure:
I. Skin Layers :
a. Epidermis b. Dermis -
C. Hypodermis (Subcutaneous Tissue) -
Layers of the Epidermis:
FIGURE 1
FIGURE 2
Skin color
I. Determined by combo of:
A.
B.
C.
II. Pigments
A. melanin - 3 types (black, brown, yellow)
1. melanocytes in stratum basale transfer pigment to keratinocytes
2. freckles & pigmented moles caused by: _______________________
3. Define: solar elastosis - ____________________________________
B. Carotene - yellow to orange
1. lipid soluble vitamin A precursor
2. accumulates in ___________________and ______________ cells
C. Hemoglobin
1. ______________________ color of oxygenated blood
2. more obviously detected in ____________ skin
II. Blood circulation
A. increase in flow - _________________________________________
B. decrease in flow - ________________________________________
IV. Diagnostics
A. skin color is often used as a first line diagnostic tool
B. Influenced by ______________ or _______________ states.
List color of skin AND possible causes for each of the following:
1. cyanosis
2. erythema
4. jaundice
5. bronzing
6. bruises (hematomas)
Derivatives of skin
I.
Hair Structure & Info
Split Ends
Hair shaft – above skin
Hair root – below skin
__________________________________
smooth muscle regulated by
cold/fright – contraction pulls hair
upright causing “goose bumps”
_________________________________
actively mitotic area in bulb – directly
surrounds papilla
_________________________________
capillary know in bulb for hair
nourishment
__________________________________
expanded deep end of follicule
a. Pigment
i. caused by proportions of 3 melanin types
ii. gray/white hair - melanin replaced by air bubbles in shaft
b. hair types
i. lanugo
ii. vellus
iii. terminal
c. hair growth
i. influenced by: (in this order)
1. nutrition - main influence
2. hormones
3. blood circulation
ii. cycles
1. growth phase: actively mitotic vs. resting phase: follicle atrophies
2. scalp - 4 year growth - eyebrows - 3 or 4 months growth
iii. baldness ( alopecia )
1. male pattern baldness - sex linked recessive genetic trait
2. minoxidil - know background, current use, & popularity
3. coarse repl. by vellus - progresses posteriorly
4. thinning – can be caused by medications, nutrition, stress, etc.
II. nails - know diagram
III. Glands
Sebaceous (oil) glands
 waterproofing
 softens & lubricates skin and hair
 Open into ______________________
 bactericidal effect
 secretion stimulated by hormones
 List imbalance:
sudoriferous (sweat) glands apocrine
glands
 duct opens into ________________
 axillary & anogenital region - begin to
function at puberty
 know sweat composition
ceruminous glands (not on diagram)
 modified apocrine gland
 external 1/3 of ear canal
sudoriferous (sweat) glands. eccrine
glands
 duct opens to __________________
 know sweat composition & pH
 regulated by sympathic NS to assist
in ______________________________