1. Integumentary System
Chapter 6
6-1

2. Chapter 6 Integumentary System (Skin and accessory organs)
Composed of several tissues
Maintains homeostasis
Protective covering
Retards water loss
Regulates body temperature
Houses sensory receptors
Contains immune system cells
Synthesizes chemicals
Excretes small amounts of waste
6-2

3. Layers of Skin
Epidermis
Dermis
Subcutaneous layer
or hypodermis
6-3

4. Epidermis lacks blood vessels keratinized
thickest on palms and soles, thinnest on eyelid ( mm)
melanocytes provide melanin
rests on basement membrane
stratified squamous
6-4

5. Epidermis Layers of Epidermis stratum corneum stratum lucidum
fully keratinized
stratum lucidum
only in palms and soles
stratum granulosum
granular layer
stratum spinosum
thick layer
stratum basale
deepest layer, can reproduce
6-5

6. Dermis on average 1.0-2.0mm thick dermal papillae
binds epidermis to underlying tissues
irregular dense connective tissue
muscle cells
nerve cell processes
blood vessels
hair follicles
glands
6-6

7. Subcutaneous Layer (hypodermis)
loose connective tissue
adipose tissue
insulates
major blood vessels
6-7

8. Hair Follicles epidermal cells tube-like depression
extends into dermis
hair root
reproductive cells
hair papilla
contains blood vessels
hair shaft
dead epidermal cells
melanin, trichosiderin
arrector pili muscle
6-8

9. Nails protective coverings* nail plate nail bed lunula
keratinized epithelial cells
nail bed
surface of skin
lunula
most active growing region
6-9

10. Glands Sebaceous Glands usually associated with hair follicles
secrete sebum
fatty material and cellular debris
keeps hair and skin soft, pliable, waterproof
absent on palms and soles
6-10

11. Glands sudoriferous glands (sweat) widespread in skin
deeper dermis or hypodermis
eccrine glands
most numerous
respond to temp elevation
duct opens superficially at pore
forehead, neck, back
apocrine glands
develop a scent
duct opens into hair follicle
active at puberty
respond to emotion, pain, arousal
axilla, groin, areola
ceruminous glands
ear wax
mammary glands
milk
6-11

12. Regulation of Body Temperature
6-12

13. Problems in Temperature Regulation
Hyperthermia – abnormally high body temperature
Hypothermia – abnormally low body temperature
6-13

14. Skin Color Genetic Factors Physiological Factors
varying amounts of melanin
varying size of melanin granules
albinos lack melanin
Physiological Factors
dilation of dermal blood vessels
constriction of dermal blood vessels
carotene
jaundice
Environmental Factors
sunlight
UV light from sunlamps
X rays
6-14

15. Healing Cuts Shallow cuts Deep cuts
Epithelial cells around margin stimulated to undergo mitosis faster than normal
Deep cuts
Escaping blood forms a clot
Mainly fibrin (fibrous protein), blood cells, platelets
Tissue fluids seep into clot and dry: scab
Fibroblasts migrate to injury and form collagenous fibers that bind the edges of wound
Connective tissue releases growth factors to stimulate growth.
Blood vessels extend into wound.
Phagocytic cells remove dead cells
Scab falls off
The larger and deeper the injury, the more connective tissue is formed, the more likely scar tissue will be visible

16. Healing of Cuts
6-15

17. Healing of Burns First degree burn – superficial partial-thickness
epidermis only
Second degree burn – deep partial-thickness
epidermis and some dermis
skin grows from surviving accessory organs’ epithelial cells
Third degree burn – full-thickness
skin must grow from margin of burn
autograft
homograft
various skin substitutes
extensive scars
6-16

18. Second Degree Burn
Fluid escapes from damaged dermal capillaries forming blister
Healing occurs from the epithelial cells of surviving accessory organs.
Cells divide and grow out to surface of dermis, spread over it, and forms new epidermis.
Eventually skin completely covers area.
No scar tissue should form.

19. Third Degree Burn Injured skin becomes dry and leathery
Healing can only occur from the surviving epithelial cells growing inward from the margin of the wound.
Auto graft: moving your skin from undamaged area to damaged area.
Homograft: using cadaver skin to temporarily cover wound to prevent infection.
Various skin substitutes: cultured skin from lab
Scar tissue will form

20. Rule of Nines
6-17

21. Life Span Changes Dermis becomes reduced
Loss of fat
Inability to control body temperature
Hair thins
Number of hair follicles decrease
Impaired nail growth
Sensory receptors decline
Less vitamin D production
Sebaceous glands secrete less oil
Scaly skin
Wrinkles
Sagging
Melanin production slows
Age spots
6-18