1. Slides 1 to 51
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

2. Integumentary Structure/Function
Components of the Integumentary System
Figure 5-1

3. Integumentary Structure/Function
Integumentary* System Components
Cutaneous** membrane
Epidermis – top layer (thinner)
Dermis – below epidermis (thicker)
Accessory structures
Subcutaneous layer (hypodermis)
* integumentary means “covering”
* cutaneous means “skin”
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. Integumentary Structure/Function
Main Functions of the Integument
Protection / Waterproofing
keratinized layer of dead cells
white blood cells
Temperature maintenance
sweat glands
capillaries
Synthesis and storage of nutrients
subcutaneous adipose tissue
Sensory reception
temp., touch, pain
Excretion and secretion
sweat
oil / wax
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

5. Integumentary Structure/Function
The Epidermis
Stratified squamous epithelium
Several distinct cell layers
Thick skin—five layers
On palms and soles
Thin skin—four layers
On rest of body
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6. Integumentary Structure/Function
The Structure of the Epidermis
stratum = layer
Figure 5-2

7. Integumentary Structure/Function
Cell Layers of The Epidermis
(from bottom up)
Stratum germinativum = growing/dividing layer
Stratum spinosum = spiny layer
Stratum granulosum = grainy layer
Stratum lucidum (in thick skin) = clear layer
Stratum corneum = horny layer
Dying superficial layer (topmost)
accumulation of keratin (a tough, water resistant protein)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

8. Integumentary Structure/Function
Cell Layers of The Epidermis
Stratum germinativum
Basal layer
Stem cells
Mitotic cell division layer
Source of replacement cells
melanocytes
Synthesize melanin = brown pigment
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

9. Integumentary Structure/Function
Cell Layers of the Epidermis
Intermediate layers
Stratum spinosum (spiny layer)
Superficial to stratum germinativum
Stratum granulosum (grainy layer)
Keratin granules in cytoplasm
No cell division
Stratum lucidum (clear layer)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

10. Integumentary Structure/Function
Cell Layers of the Epidermis
Stratum corneum
Most superficial layer
Flattened (squamous) cells
Dead cells
Abundant keratin
Keratinized (also, cornified)
Tough, water-resistant protein
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

11. Integumentary Structure/Function
Sources of Skin Color
Melanocytes
make pigment, melanin
melanin provides UV protection
gives reddish-brown to brown-black color
Carotene
a pro-vitamin (gets converted to vitamin A)
contributes orange-yellow color
provided from diet
Hemoglobin
red blood pigment
carries O2 to tissues and some CO2 away from tissues
The carotenes possess antioxidant properties. Vitamin A serves several biological functions including involvement in the synthesis of certain glycoproteins. Vitamin A deficiency leads to abnormal bone development, disorders of the reproductive system, xerophthalmia (a drying condition of the cornea of the eye), and ultimately death.

12. Integumentary Structure/Function
Melanocytes
Figure 5-3

13. Integumentary Structure/Function
Effects of UV Radiation
Beneficial effect
Activates synthesis of vitamin D3
Harmful effects
Sun burn
Wrinkles, premature aging
Malignant melanoma (bad)
Basal cell carcinoma (not too bad)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

14. Integumentary Structure/Function
Two Important Types of Skin Cancer
Figure 5-4
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

15. Integumentary Structure/Function
Key Note
The epidermis is a multi-layered, flexible, self-repairing barrier that prevents fluid loss, provides protection from UV radiation, produces vitamin D3, and resists damage from abrasion, chemicals, and pathogens (=disease-causers)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

16. Integumentary Structure/Function
Layers of the Dermis
(from top down)
Papillary layer
Underlies epidermis
Named for dermal papillae*
Loose connective tissue
Supports, nourishes epidermis
Provides sensory nerves, lymphatics, and capillaries
*papillae = “little fingers”
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

17. Integumentary Structure/Function
Layers of the Dermis
Reticular layer
Tough, dense, fibrous layer
collagen fibers
limit stretch
elastin fibers
provide flexibility
blends into papillary layer (above)
blends into subcutaneous layer (below)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

18. Integumentary Structure/Function
Other Dermal Components
Epidermal accessory organs
Cells of connective tissues proper
Communication with other organ systems
Cardiovascular
Lymphatic
Nervous
Sensation
Control of blood flow and secretion
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

19. Integumentary Structure/Function
Key Note
The dermis provides mechanical strength, flexibility, and protection for underlying tissues. It is highly vascular (lots of blood vessels) and contains a variety of sensory receptors that provide information about the external environment.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

20. Integumentary Structure/Function
The Subcutaneous Layer
Composed of loose connective tissue
Stabilizes skin position
Loosely attached to dermis above
Loosely attached to muscle below
Contains many fat cells (adipose tiss.)
Provides thermal insulation
Cushions underlying muscle tissue.
Safely receives hypodermic needles
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

21. Integumentary Structure/Function
Hair Follicles
The arrector pili muscles are what produce “goose bumps.”
Figure 5-5(b)

22. Integumentary Structure/Function
Accessory Structures
Sebaceous glands (oil glands)
Oily secretion
Sebum
Hair shaft lubricant
Sebaceous follicle
Skin lubricant
Skin waterproofing
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

23. Integumentary Structure/Function
The Structure of Sebaceous Glands and Their Relationship to Hair Follicles
Figure 5-6

24. Integumentary Structure/Function
Sweat Glands
Apocrine
Odorous secretion (“funky”)
Absent before puberty
Present in axilla (=armpit), groin
Merocrine
Watery sweat (~1% NaCl)
For heat loss
Widely present in skin (up to 500/cm2)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

25. Integumentary Structure/Function
Sweat Glands
Figure 5-7

26. Integumentary Structure/Function
Key Note
The skin plays a major role in controlling body temperature. It acts as a radiator, with the heat being delivered by the dermal circulation and removed primarily by the evaporation of sweat or perspiration.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

27. Skin Injury and Repair Four Stages in Skin Healing Inflammation
Blood flow increases
Phagocytes attracted
Scab formation
Cell division and migration
Scar formation
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

28. Bleeding occurs at the site of injury immediately after the injury, and mast cells in the region trigger an inflammatory response.
Epidermis
Dermis
Figure 5-9
2 of 5
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

29. Macrophages and fibroblasts
Bleeding occurs at the site of injury immediately after the injury, and mast cells in the region trigger an inflammatory response.
After several hours, a scab has formed and cells of the stratum germinativum are migrating along the edges of the wound. Phagocytic cells are removing debris, and more of these cells are arriving with the enhanced circulation
in the area. Clotting around the edges
of the affected area partially isolates
the region.
Epidermis
Scab
Migratory
epithelial
cells
Macrophages
and
fibroblasts
Dermis
Sweat
gland
Granulation
tissue
Figure 5-9
3 of 5
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

30. Fibroblasts = connective tissue cells that secrete fibers.
One week after the injury, the scab has been undermined by epidermal cells migrating over the meshwork produced by fibroblast activity. Phagocytic activity around the site has almost ended, and the fibrin clot is disintegrating.
Fibroblasts
Figure 5-9
4 of 5
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

31. One week after the injury, the scab has been undermined by epidermal cells migrating over the meshwork produced by fibroblast activity. Phagocytic activity around the site has almost ended, and the fibrin clot is disintegrating.
After several weeks, the scab has been shed, and the epidermis is complete. A shallow depression marks the injury site, but fibroblasts in the dermis continue to create scar tissue that will gradually elevate the overlying epidermis.
Scar
tissue
Fibroblasts
Figure 5-9
5 of 5
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

32. Bleeding occurs at the site of injury immediately after the injury, and mast cells in the region trigger an inflammatory response.
After several hours, a scab has formed and cells of the stratum germinativum are migrating along the edges of the wound. Phagocytic cells are removing debris, and
more of these cells are arriving with the enhanced circulation in the area. Clotting around the edges of the affected area partially isolates the region.
Epidermis
Scab
Migratory
epithelial
cells
Macrophages
and
fibroblasts
Dermis
Sweat
gland
Granulation
tissue
One week after the injury, the scab has been undermined by epidermal cells migrating over the meshwork produced by fibroblast
activity. Phagocytic activity around the site has almost ended, and the fibrin clot is disintegrating.
After several weeks, the scab has been shed, and the epidermis is complete. A shallow depression marks the injury site, but fibroblasts in the dermis continue to create scar tissue that will gradually elevate the overlying epidermis.
Scar
tissue
Fibroblasts
Figure 5-9
1 of 5
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

33. Squamous cell carcinoma Melanoma
Skin Cancer
Basal cell carcinoma
Squamous cell carcinoma
Melanoma

34. Basal Cell Carcinoma Least malignant and most common skin cancer
Stratum germinativum cells proliferate and invade the dermis and hypodermis
Slow growing and do not often metastasize (spread around body)
Can be cured by surgical excision in 99% of the cases

35. Squamous Cell Carcinoma
Arises from keratinocytes of stratum spinosum
Arise most often on scalp, ears, and lower lip
Grows rapidly and metastasizes if not removed
Prognosis is good if treated by radiation therapy or removed surgically

36. Melanoma
Cancer of melanocytes is the most dangerous type of skin cancer
Melanomas have the following characteristics (“ABCD rule”):
A: Asymmetry; the two sides of the pigmented area do not match
B: Border is irregular and exhibits indentations
C: Color (pigmented area) is black, brown, tan, and sometimes red or blue
D: Diameter is larger than 6 mm (size of a pencil eraser)

37. Melanoma
Treated by wide surgical excision accompanied by immunotherapy
Chance of survival is poor if the lesion is over 4 mm thick

38. Burns First-degree – only the epidermis is damaged
Symptoms include localized redness, swelling, and pain
Second-degree – the epidermis and upper regions of dermis damaged
Symptoms mimic first degree burns, but blisters also appear
Third-degree – involve entire thickness of the skin
Burned area appears gray-white, cherry red, or black, and there is no initial edema nor pain (since nerve endings are destroyed)

39. Rule of Nines Estimates the severity of burns
Burns considered critical if:
Over 25% of the body has second-degree burns
Over 10% of the body has third-degree burns
There are third-degree burns on face, hands, or feet
Figure 5.9a