1. Chapter 4
Integumentary System

2. Basic Skin Functions

3. Keeps water and other molecules in
Keeps water and other molecules out
* Keratin – water-proofing protein
Insulates
Cushions deeper organs

4. Protects from:
a. Mechanical damage – cuts/bumps
b. Chemical – acids and bases
c. Thermal
d. UV
e. Bacteria

5. Regulates heat loss with a capillary network and sweat glands
Mini excretory system (urea, salts, water)
Manufactures proteins and vitamin D
Sensory receptors

7. Structure of the Skin
Two Layers
Epidermis
Dermis

8. Deep to the dermis is the Hypodermis or subcutaneous layer
This Layer is deep to the dermis but is not part of the skin - anchors

9. A. Epidermis 5 layers Avascular – no blood
Cells are made in the bottom layer and move up
New epidermis – 25 to 45 days

10. Melanin Skin pigment Yellow to brown/black
Produced by melanocytes in the bottom layer
Tanning occurs when melanocytes produce more pigment
Melanin pigment umbrella over nuclei
Freckle – local concentration of melanin

11. B. Dermis Strong stretchy envelope that holds the body together
Two layers
Fingerprints originate from projections in this layer

12. Deepest layer – blood vessels (temperature), sweat, oil glands
Has collagen – toughness of the dermis
Elastic fibers – elasticity of the skin
- wrinkles when lost

13. Skin Color Is caused by three pigments 1. amount and kind of melanin
2. Amount of carotene – orange
3. Amount of oxygen in hemoglobin
(when there is a lot of oxygen – red)
(when there is little oxygen – blue)

14. Affected by emotional stimuli and disease
Erythema – redness
Pallor – pale
Jaundice – yellow – liver
Bruises – blood vessels damaged and blood leaks out
Cyanosis – blue cast to skin
- not enough oxygen

15. Appendages of the Skin

16. I. Cutaneous glands (Exocrine) – give off
Sebaceous (oil) glands
1. empty on to a hair follicle
2. produce sebum – lubricant – kills
bacteria
3. Duct blocked - zit

17. Sweat glands
1. sweat – clear secretion that is
primarily water plus NaCl, vitamin C,
traces of metabolic waste (urea)
2. Important for heat regulation
3. Hot days – lose up to 7L

18. II. Hair and Hair Follicles – produce hair
Protective functions
Root – part in the follicle
Shaft – part growing out of the skin
Made of dead cells full of keratin

19. III. Nails Scalelike, modification of the epidermis
Free edge, body, root
Made of dead cells full of keratin

20. Homeostatic Imbalances of the Skin
There are 1000’s

21. 1. Infections and Allergies

22. Athlete’s Foot Itchy red peeling condition between the toes
Caused by: Fungus

23. Athlete’s Foot

24. Boils Inflammation of the hair follicles and sebaceous glands
Staphylococcus aureus
Caused by: inflammation of a follicle

25. Boils

26. Carbuncles
Composite boils
Caused by: bacteria infection

27. Carbuncles

28. Carbuncles

29. Cold Sore Small fluid filled blisters that itch and sting
Caused by: Herpes simplex infection
Virus in cutaneous nerve
Dormant until emotional upset, fever, or UV light

30. Cold Sore

31. Contact Dermatitis - Poison Ivy
Itchy redness, swelling and blistering
Caused by: Exposure to chemicals

32. Poison Ivy

33. Impetigo Pink water filled lesions Around mouth and nose
Yellow crust and rupture
Caused by: Highly contagious staph infection
Common in elementary kids

34. Impetigo

35. Psoriasis Chronic condition Reddened epidermal lesions
Dry silvery scales
Can be disfiguring
Caused by: cause is unknown – hereditary?
Attack often triggered by trauma, infection hormonal changes, stress

36. Psoriasis

37. Acne
Caused by: blockage in the hair follicle

38. 2. Burns

39. Skin is as thick as a paper towel
Damage affects all other body systems
Burn – tissue damage and cell death caused by heat, UV radiation, chemicals

40. Two Life Threatening Problems
Body loses precious supply of fluids
Infection

41. Rule of the Nines Estimates fluid loss
11 areas of the body, 9% each, 1% area around the genitals

42. Burn Classification

43. First Degree Epidermis only Red/swollen Re-growth – cells still ok
Partial thickness burn

44. Second Degree Epidermis and top of dermis Blisters
Re-growth – cells still ok
Partial thickness burns

45. Third Degree Full thickness burn Area blanched or blackened
Nerves destroyed
No re-growth - graft

46. Burns are Critical if: More than 25% of the body has second degree
10% had third degree
Third degree on face, hands or feet

47. Skin Cancer

48. Basal Skin Carcinoma

55. Squamous Cell Carcinoma

60. Melanoma

68. The End