Chapter 5
 Integument/Integument
system: Debated as
to whether or not your skin is an organ or
organ system
 Accounts for 16% of body weight
 2 Major Components:
 1-Skin or Cutaneous Membrane
 Epidermis
 Dermis
 Hypodermis
 2-Accessory Structures
 Nails
 Exocrine glands
 Protection
 Excretion
(salts, water, organic wastes)
 Maintenance of body temp
 Synthesis of vitamin D3
 Storage of nutrients (adipocytes)
 Detection of touch, pressure, pain, etc.
 Skin
Epidermis (superficial)
 Dermis
 Hypodermis (deep)

 Thin
skin=made of 4 layers of stratified
Squamous tissue

Most of body
 Thick

skin=made of 5 layers
Hands and feet
Made of Stratified Squamous epithelium
 Stratum
 Stratum
 Stratum
 Stratum
 Stratum

Corneum (superficial)
Lucidum
Granulosum
Spinosum
Basale or Germinativum (deep)
Cells eventually pass through all layers or
can eventually be found
 Surface
skin (most superficial)
 Highly keratinized: thick, interwoven
 15-30 days to get from stratum basale to stratum
corneum
 Stay at stratum corneum for 2 weeks b/f shed
 Loose 500 mL (1 pint) water a day through skin
 Blisters:
water retention between
dermis/epidermis under high stress
 Found
in thick skin
 Glassy, tough
 Filled with keratin
 Fibrous proteins—make up your hair and nails
 Layer missing in “thin” areas
 “Grainy
 3-5
Layer”
layers
 Have stopped dividing at this time
 High in keratin
 Makes cells flatter and thinner
 “Spiny
Layer”
 8-10 layers
 Langerhans Cells
=participate in immune
response
 Innermost
 Closest
to basement membrane
 Sends projections into dermis (below
basement membrane)
Called epidermal ridges
 Give skin the whorls of fingertips

 Basal
cells =stem cells to make more skin
 Merkel Cells =sense touch where no hair is present
 Melanocytes =skin tone
 Due
to interaction of Epidermal
Pigmentation and Dermal Circulation
2
Pigments that control your skin color
 1-Carotene (orange-yellow)
Found in stratum corneum
 2-Melanin (brown, yellow-brown, black)
 Found in stratum basale
 protects us from UV radiation
 Melanocytes produce
 Dark skin = increased amount of Melanin
production not increased amount of
individual Melanocytes

 Gives
pale or flushed look
 Better circulation =flushed
 Reduced circulation=pale
 Damages
DNA of the cell, causing mutations
and promoting cancer development
 Read
bottom of 147(Melanocytes-Dermal
Circulation)
 When
exposed to sun, epidermal cells make D3,
then the liver converts D3, and the kidney makes
calcitriol.
Calcitriol=ability to absorb calcium and phosphorous
(no calcitriol=impaired bone maintenance and
growth)

 Freckles
 Areas
where melanocytes are producing
a higher than normal rate of melanin.
 Birthmarks
 Non-vascular

Overgrowth of melanocytes
 Tattoo’s
Papillary Layer
 Areolar tissue, capillaries,
sensory neurons
 Supplies epidermis
2. Reticular Layer
 Collagen and elastic fiber
1.
 Collagen
fibers=strong, resists stretching BUT bend
easily
 Elastic fibers=stretch and return
=flexible, elastic dermis
 Aging, hormones, and excess UV = weakened fibers 
Wrinkles
 Excessive stretching past fibers capabilities lead to
damaged fibers=stretch marks
 Caused by: pregnancy, major weight loss/gain
 SOLUTION: Retin-A from vitamin A increases blood
flow to dermis which increases chances for repair
5
million hairs
 98% not on head
 Hair
Follicle=organ when
hair is grown
 Hair Root=anchors hair to
skin
 Hair Shaft=part you see
 Is


hair living?
No-Comprised of non-living cells
Hair follicles are
 How



is color determined?
Pigment produced by
melanocytes
The biochemistry of these
structures is affected by DNA
Hormonal/Environmental affects
 Protection
(eye lashes, head,
sensory, ears, nose)
 Root hair plexus=sensory nerve
around each hair follicle
 Arrector Pilli-smooth muscle
attached to hair follicle=when
stimulated, contracts, causes
“goose bumps”
 Stimulated by emotional states,
response to cold
 Hair
growth cycle=2-5 years
 .33mm/day
 Hair loss occurs when the follicle becomes
inactive and shrinks
 Over time, the connection breaks=hair loss
 The old hole sheds, new one forms
 Male

Pattern Baldness
Decrease in hormones circulating in the blood
 Alopecia




1 in every 100,000
Complete hair loss all over body
Genetic
Causes death of hair follicles
 Sebaceous


Share a duct with hair
Waxy, oil secretions
 Apocrine
groin)



Sweat Glands (armpits, around the nipples,
Odorous, sticky
Through hair follicle
Begin at puberty
 Merocrine


(Oil Glands-Holocrine)
Sweat Glands (all other sweat)
2-5 million
High numbers in palms/soles
 Provides
protection to finger
 Nail Body cover nail bed
 Production at nail root
 Lunala is pale=lack of blood
vessels
 Is dead, tightly compressed
keratin packed cells
 Not
part of integument but
important for stabilization



Areolar/Adipose tissue
Elastic
Area for injections