1. Human Anatomy and Physiology I
The Integumentary System
Chapter 5
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2. Chapter 5 Outline Overview of the skin Skin Cancers Burns Epidermis
Hypodermis
Appendages of the skin
Sweat glands, Sebaceous glands, Hair,
Nails
Functions
Skin Cancers
Burns

3. Skin (Integument) Consists of three major regions
Epidermis—superficial region
Dermis—middle region
Hypodermis—deepest region

4. Hair shaft
Dermal papillae
Epidermis
Subpapillary
vascular plexus
Papillary
layer
Pore
Appendages
of skin
Dermis
Reticular
layer
• Eccrine sweat
gland
• Arrector pili
muscle
Hypodermis
(superficial fascia)
• Sebaceous
(oil) gland
• Hair follicle
Nervous structures
• Hair root
• Sensory nerve fiber
Cutaneous vascular
plexus
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Adipose tissue

5. Epidermis Keratinized stratified squamous epithelium
Cells of Epidermis

6. Dermis - supplied with blood vessels, nerve fibers, lymphatic vessels
Connective tissue
- binds epidermis to tissue below
- supplied with blood vessels, nerve fibers, lymphatic vessels
Layers
1. Papillary layer
2. Reticular layer

7. Skin Color Three pigments contribute to skin color Melanin Carotene
Yellow to reddish-brown to black, responsible for dark skin colors
Carotene
Yellow to orange, most obvious in the palms and soles
Hemoglobin
Responsible for the pinkish hue of skin

8. Appendages of the Skin Derivatives of the epidermis Sweat glands
Oil glands
Hairs and hair follicles
Nails

9. Sweat Glands Eccrine: forehead, neck, back, palms, soles
- respond to increased body temperature, or stress
2. Apocrine: axillary regions, groin, around nipples
- respond to sexual arousal, fear, pain, emotional upset
3. Ceruminous: produce cerumen (earwax) - protection
Secretory cells
Dermal connective
tissue
Duct
Sebaceous
gland
Sweat pore
Eccrine

10. Sebaceous (Oil) Glands
Function
produce sebum
- waterproofs and softens skin and hair
Sebaceous
gland duct
Hair in
hair follicle
Secretory cells
Dermal
connective
tissue
gland
Sweat
pore
Eccrine

11. Which of the following is not part of the dermis?
Papillary layer
Melanocytes
Sebaceous glands
Hair follicles

12. Hair Function Distribution
Alerts the body to presence of insects on the skin
Guards the scalp against physical trauma, heat loss, and sunlight
Distribution
Entire surface except palms, soles, lips, nipples, and portions of external genitalia

13. Hair Structure Hair develops from epidermal cells at base of follicle
Older cells are pushed outward; become keratinized
Hair pigments: melanins (yellow, rust brown, black)
Gray/white hair: decreased melanin production, increased air bubbles in shaft

14. Follicle wall
• Connective
tissue root sheath
Hair shaft
• Glassy membrane
• External epithelial
root sheath
• Internal epithelial
root sheath
Arrector
pili
Hair root
• Cuticle
Sebaceous
gland
• Cortex
• Medulla
Hair root
Hair matrix
Hair bulb
Hair papilla
Subcutaneous
adipose tissue

15. Hair Thinning and Baldness
Alopecia
Hair thinning in both sexes after age 40
True baldness
Genetically determined and sex-influenced condition
Male pattern baldness is caused by follicular response to DHT

16. Nails
Scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes
Keratinized epidermal cells
Protective

17. Functions of the Integumentary System
Protection
Chemical barriers
Skin secretions fight bacteria
Melanin protects against UV rays
Physical/mechanical barriers
Keratin and glycolipids block most water and water- soluble substances
Limited penetration of skin by lipid-soluble substances
Biological barriers
Dendritic cells and macrophages

18. Functions of the Integumentary System
Body temperature regulation
Sweat for evaporative cooling
Constriction of dermal capillaries to prevent heat loss
Cutaneous sensations
Pain
Pressure
Temperature

19. Functions of the Integumentary System
Metabolic functions
Synthesis of vitamin D
Blood reservoir
— Up to 5% of body’s blood volume
Excretion
— Salt and nitrogenous wastes in sweat

20. Did You Know?
Every minute 30, ,000 dead skin cells fall off or are sloughed off your body.
In one month, your body will have a whole new layer of skin.
You will shed about 40 pounds of skin during your lifetime.

21. Skin Cancer Three major types Basal cell carcinoma
Least malignant, most common
Squamous cell carcinoma
Second most common
Melanoma
Most dangerous

22. Basal Cell Carcinoma
Stratum basale cells proliferate and slowly invade dermis and hypodermis
Cured by surgical excision in
99% of cases

23. Squamous Cell Carcinoma
Involves keratinocytes of stratum spinosum
Most common on scalp, ears, lower lip, and hands
Good prognosis if treated by radiation therapy or removed surgically

24. Melanoma Characteristics (ABCDE rule)
A: Asymmetry; the two sides of the pigmented area do not match
B: Border exhibits indentations
C: Color is black, brown, tan, and sometimes red or blue
D: Diameter is larger than 6 mm (size of a pencil eraser)
E: Evolving is any change in elevation, itching, scabbing, or bleeding

25. Melanoma Involves melanocytes
Highly metastatic and resistant to chemotherapy
Treated by wide surgical excision accompanied by immunotherapy

26. Burns Causes Heat, electricity, radiation, certain chemicals Results
Tissue damage, denatured protein, cell death
Immediate threat
Dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shock

27. Burns First degree Second degree Epidermal damage only
Localized redness, edema
(swelling), and pain
Second degree
Epidermal and upper
dermal damage
Blisters appear
1st degree
burn
2nd degree

28. Burns Third degree Entire thickness of skin damaged
Gray-white, cherry red, or black
No initial edema or pain
(nerve endings destroyed)
Skin grafting usually
necessary
3rd
degree
burn

29. Homeostatic Imbalances
Vitiligo
Most prevalent skin
pigmentation disorder
Loss of melanocytes
Uneven skin pigmentation
Autoimmune disorder

30. Homeostatic Imbalances
Eczema
inflammation of the
epidermis
redness, edema, itching and dryness, crusting, flaking, blistering, cracking, oozing, or bleeding

31. Tissue Repair 1. Hemostasis and Inflammation
hemostasis = blood clotting
blood platelets adhere to the wound and recruit more platelets to form a clot.
fibrin strengthens the clot
Inflammation is triggered by mast cells
Capillaries dilate to allow white blood cells through, causing pink appearance and increased temperature.

32. Tissue Repair 2. Proliferation
macrophages consume debris and bacteria, and signal other cell types to come and start the next phase
Granulation tissue replaces the blood clot
Fibroblasts produce collagen to strengthen and hold the wound together
Epidermis begins to regenerate

33. Tissue Repair 3. Remodeling/ Maturation
Repairs are strengthened by more organized collagen
Wound continues to contract
Collagen-rich scar tissue has replaced wound
Scab detaches