1. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Integumentary System Chapter 4

2. Human Anatomy, 3rd edition Prentice Hall, © 2001 Introduction –Structure Epidermis Dermis Hypodermis –Functions of the skin

3. Human Anatomy, 3rd edition Prentice Hall, © 2001 The “Birthday Suit” –Combination of 4 main tissues Epithelial – outer layer Connective – underlies dermis Smooth Muscle – goose bumps Nervous – sensory receptors

4. Human Anatomy, 3rd edition Prentice Hall, © 2001 Functions of the Skin –Protection –Temperature regulation –Sensations –Storage of chemical compounds –Excretion of wastes –Synthesis of compounds –Determines characteristics

5. Human Anatomy, 3rd edition Prentice Hall, © 2001 Structure of the Skin –2 principal parts Epidermis Dermis –Beneath the dermis Subcutaneous layer

6. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Skin

7. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epidermis –Stratified squamous epithelium –Over most of the body it’s thin –Approximately every month we shed entire skin surface

8. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epidermis

9. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epidermis

10. Human Anatomy, 3rd edition Prentice Hall, © 2001 Replacement of Epidermal Cells –Base of epidermis Cuboidal cells divide by mitosis New cells are pushed toward surface –New epidermal cells produce keratin –Cells are flattened as they are pushed upwards –Cells die –Outermost layer Cells are dead, filled with keratin –Takes about two weeks for an epidermal cell to move from the bottom layer to the top

11. Human Anatomy, 3rd edition Prentice Hall, © 2001 Pigments –Melanin Produced by melanocytes Skin color varies Protect skin from UV rays –Carotene –Albino

12. Human Anatomy, 3rd edition Prentice Hall, © 2001 Melanocytes and Melanin

13. Human Anatomy, 3rd edition Prentice Hall, © 2001 Melanocytes and Melanin

14. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epidermis and Dermis –Epidermis is avascular –Dermis is highly vascular –Epidermis receives nourishment from dermis –Cells far away from nourishment die

15. Human Anatomy, 3rd edition Prentice Hall, © 2001 Dermis –Largest part of the skin –Connective tissue –Contains Blood vessels Nerves Glands Hair follicles

16. Human Anatomy, 3rd edition Prentice Hall, © 2001 Papillary Layer of the Dermis –Most superficial layer –Surface area increased by papillae Form fingerprints –Has lots of sensory receptors Papillary Layer

17. Human Anatomy, 3rd edition Prentice Hall, © 2001 Papillary Layer

18. Human Anatomy, 3rd edition Prentice Hall, © 2001 Fingerprints

19. Human Anatomy, 3rd edition Prentice Hall, © 2001 Deeper Layer of the Dermis –Deeper layer –Dense connective tissue –Contains Blood vessels Glands Deep pressure receptors –Attached to underlying organs by the subcutaneous layer

20. Human Anatomy, 3rd edition Prentice Hall, © 2001 Subcutaneous Layer –Loose connective tissue Packed with adipose cells –Stabilizes position of skin

21. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Skin

22. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epidermal Derivatives –Hair –Glands –Nails

23. Human Anatomy, 3rd edition Prentice Hall, © 2001 Functions of Hair –Protection –Thermoregulation –Sensory –Minor role in humans

24. Human Anatomy, 3rd edition Prentice Hall, © 2001

25. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hair Structure –Shaft Superficial portion –Root Below the surface

26. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hair Structure –Medulla Soft core of hair –Cortex Hard core that gives hair its stiffness –Cuticle Outermost layer of hair

27. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hair Structure

28. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hair Structure –Hair develops in follicles Downward continuation of epidermis

29. Human Anatomy, 3rd edition Prentice Hall, © 2001 Growth of Hair –At the base of the follicle, hair papilla Contains blood vessels and nerves –Nourishes hair –Bulb Contains matrix – epithelial cells responsible for growth –Contains melanocytes

30. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hair Follicle

31. Human Anatomy, 3rd edition Prentice Hall, © 2001 Arrector Pili –Smooth muscle attaches to follicle –Raises hairs –Response to fright or cold –Function?

32. Human Anatomy, 3rd edition Prentice Hall, © 2001 Glands –Sebaceous glands Connected to hair follicles Secrete a waxy, oily substance (sebum) –Blackheads Secretion increases at puberty

33. Human Anatomy, 3rd edition Prentice Hall, © 2001 Sebaceous Glands

34. Human Anatomy, 3rd edition Prentice Hall, © 2001 Glands –Sweat glands Found just about everywhere Produce “perspiration” –Water, salt, met. Wastes Function – cooling of the body

35. Human Anatomy, 3rd edition Prentice Hall, © 2001 Glands –Scent Glands Specific type of sweat gland Found near hair follicles –Axillary & genital regions Develop at puberty

36. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Skin with Sweat Glands

37. Human Anatomy, 3rd edition Prentice Hall, © 2001 Nails –Dorsal surfaces of ends of fingers & toes –Primate feature –Grasping

38. Human Anatomy, 3rd edition Prentice Hall, © 2001 Nail Structure –Nail body –Free edge –Nail root Matrix –Lunula (moon)

39. Human Anatomy, 3rd edition Prentice Hall, © 2001 Nail Structure

40. Human Anatomy, 3rd edition Prentice Hall, © 2001 Skin Cancer –Basal Cell Carcinoma –Squamous Cell Carcinoma –Melanoma

41. Human Anatomy, 3rd edition Prentice Hall, © 2001 Basal Cell Carcinoma

42. Human Anatomy, 3rd edition Prentice Hall, © 2001 Squamous Cell Carcinoma

43. Human Anatomy, 3rd edition Prentice Hall, © 2001 Melanoma