1. The Integumentary System
Chapter 5
The Integumentary System

2. Intro to Integumentary
The integumentary system contains the cutaneous membrane & accessory structures
Cutaneous membrane (skin) composed of epidermis & dermis
Hypodermis separates integument from deeper tissues

4. Functions of integumentary system:
Protection
Temperature maintenance
Synthesis of nutrients
Sensory reception
Excretion & secretion

5. Intro Checkpoint
List the general functions of the integumentary system.

6. 5-1: The Epidermis Epidermis layers
Thick skin (palms of hands, soles of feet)
Thin skin (rest of body)
Deepest layer of epidermis contains melanocytes
Make melanin—brown pigment

7. Middle layer of epidermis produce keratin to toughen skin
Surface layer of epidermis contains dead, keratinized cells

8. 5-1 Checkpoint
Dandruff is caused by excessive shedding of skin cells from the outer layer of skin in the scalp. Which epidermal layer produces dandruff?
Will the sanding off of fingerprints permanently remove the fingerprints? Why or why not?

9. 5-2: Factors In Skin Color
The Role of Pigmentation
Carotene—orange pigment
Melanin—brown pigment
Freckles—areas of more melanin
Prevents skin damage from ultraviolet radiation
Albinos lack melanin

10. The Role of Dermal Circulation
Blood vessels in the dermis give skin a pink or flushed color
Constricting blood vessels causes pale color
Loss of oxygen causes cyanosis—blue color

11. 5-2 Checkpoint Name the two pigments in the epidermis.
Why does exposure to sunlight or sunlamps darken skin?
Why does the skin appear red during exercise?

12. 5-3: Sunlight & Skin Skin Cancers
Basal cell carcinoma & squamous cell carcinomas rarely spread; are surgically removed
Malignant melanomas are life-threatening
Usually begins in a mole

13. Risk factors for skin cancer
Caucasian, European ancestry
Prolonged exposure to sunlight
Preventing skin cancer
Wear at least SPF 15
Avoid prolonged exposure, avoid mid-day sun

14. Use ABCD Rule for examining moles for skin cancer
A. Asymmetry: mole should be uniform in shape
B. Border: edges of mole should be definite
C. Color: mole should be black, brown or tan, sometimes red or blue
D. Diameter: mole should not be larger than 6 mm

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16. 5-3 Checkpoint What are the most common types of skin cancer?
How can skin cancer be prevented?
What is the ABCD Rule for examining moles?

17. 5-4: The Dermis The dermis nourishes the epidermis
Contains elastic & collagen fibers
Blood vessels, nerves, accessory organs and glands are found in the dermis

18. 5-4 Checkpoint Describe the location of the dermis.
Where are the capillaries that supply the epidermis located?

19. 5-5: The Hypodermis
The hypodermis (subcutaneous layer) connects the skin to underlying tissues
Contains numerous adipose cells for insulation & energy storage

20. 5-5 Checkpoint
List the two terms for the tissue that connects the dermis to underlying tissues.
Describe the hypodermis.

21. 5-6: Hair Hair & Hair Follicles
Hair is a nonliving structure produced in hair follicles
Hair & Hair Follicles
Hair is formed from repeated cell divisions
Cells are pushed to the surface & die

22. The hair root anchors the hair shaft
Hair shaft covered by cuticle—overlapping cells
Hairs are shed & replaced by new hairs

23. Functions of Hair
Protect from UV, prevent entry of foreign particles, sensitivity
Arrector pili pull on hair follicles to make hair stand up (goose bumps)
Hair color determined by amounts of melanin

24. 5-6 Checkpoint Describe a typical strand of hair.
What happens when the arrector pili muscle contracts?
If a burn on the arm destroys the epidermis & deep dermis, will hair grow again in the affected area?

25. 5-7: Sebaceous & Sweat Glands
Sebaceous (Oil) Glands
Secrete oil (sebum) into hair follicles or on skin
Blocked sebaceous glands generate acne

26. Sweat Glands Apocrine glands—begin secretions at puberty
Merocrine glands—most numerous type of sweat gland
Release secretions onto skin to cool the body
Excessive sweating can lead to dehydration

28. 5-7 Checkpoint
Identify two types of exocrine glands found in the skin.
What are the functions of sebaceous secretions?

29. 5-8: Nails Nails protect the tips of the fingers & toes
Consist of a nail body (keratinized cells) over a nail bed
The cuticle folds over the nail
Blood vessels found under the nail bed

31. 5-8 Checkpoint What substance makes nails hard?
Where does nail growth occur?

32. 5-9: Steps in Skin Repair Repair of Skin Injuries
Bleeding occurs at injury site; forms a clot
A scab forms over the injured epidermis
New fibers replace damaged tissue
May form scar tissue

33. Effects of Burns First-degree (superficial)—epidermis
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Effects of Burns
First-degree (superficial)—epidermis
Redness, swelling & pain

34. Second-degree (partial thickness)—epidermis & dermis
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Second-degree (partial thickness)—epidermis & dermis
Similar to first-degree; blisters appear

35. Third-degree (full thickness)—entire thickness of skin
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Third-degree (full thickness)—entire thickness of skin
No initial pain or swelling—nerve ends burned

36. 5-9 Checkpoint
Why can skin regenerate effectively even after considerable damage has occurred?
What are the three types of burns, and what layers of the skin does each type affect?