Chapter 5

1. Chapter 5 The Integumentary System and Body Membranes

2. Objectives Classify, compare the structure of, and give examples of each type of body membrane. Describe the structure and function of the epidermis and dermis. List and briefly describe each accessory organ of the skin. List and discuss the three primary functions of the integumentary system.

3. Question What are the four major types of membranes in the body?

4. Membranes • Epithelial membranes • Mucous Membranes • Serous membranes • Pleura • Pericardium • Peritoneum • Connective Tissue Membranes

5. CLASSIFICATION OF BODY MEMBRANES • Epithelial membranes • Cutaneous membrane—the skin • More later!!

6. Classification of Body Membranes • Mucous membranes • Line body surfaces that open directly to the exterior • Produce mucus, a thick secretion that keeps the membranes soft and moist What are examples of mucous membranes?

7. SerousMembranes • Line the cavities that do not open to the outside world • Double layered • Visceral • Parietal • Serous fluid is in the cavity between them

9. Synovial Membranes • Connective tissue membranes • Do not contain epithelial components • Produce a lubricant called synovial fluid • Examples are the synovial membranes in the spaces between joints and in the lining of bursal sacs

10. Disorders of Body Membranes • Diseases • Pleurisy—inflammation of the serous membranes that line the chest cavity and cover the lungs • Peritonitis—inflammation of the serous membranes in the abdominal cavity that line the walls and cover the abdominal organs

11. Integumentary System • Integument = covering • Consists of: • Skin • Accessory Organs: • Hair • Nails • Glands • The largest organ of the body is the Skin

12. Question What are the functions of the skin?

13. Functions of Skin • Protects from injuries • Acts as barrier and regulates what enters/leaves body. • Regulates body temperature. • Synthesizes, stores vitamins. • Sensory functions

14. Functions of the Skin • Sense organ activity • Skin functions as an enormous sense organ • Receptors serve as receivers for the body, keeping it informed of changes in its environment—disorders of the skin (dermatoses)

15. Functions of the Skin • Protection—first line of defense • Against infection by microbes • Against ultraviolet rays from sun • Against harmful chemicals • Against cuts and tears • Skin grafts

16. Structure of the Skin • 3 main layers from superficial to deep 1) Epidermis Epi- derm/o -is above skin structure “structure above the skin” a. Thin cellular membrane layer

18. Structure of the Skin (cont’d) 2) Dermis Derm/o -is Skin structure “true skin” a. thick, contains connective tissue layer with collagen and elastic fibers, epithelial tissue, smooth muscle tissue, nervous tissue and blood

19. Sensory Structures of Dermis • Deep touch/pressure: Pacinian corpuscles • Light touch/pressure: Meisner’s corpuscles • Warm temperature: Free nerve endings • Cold temperature: Free nerve endings • Pain: Free nerve endings

20. Structure of the Skin (cont’d) 3) Subcutaneous tissue Sub- cutane/o -us Below skin structure “structure below the skin” a. thick, fat-containing tissue

21. Atlas of Human Anatomy in Cross Section: Section 2. Neck, Shoulders, Upper Arm, and Upper Thorax (Lungs) Key Figure 4a Ronald A. Bergman, Ph.D., Adel K. Afifi, M.D., Jean J. Jew, M.D., and Paul C. Reimann, B.S.Peer Review Status: Externally Peer Reviewed Hypodermis (Subcutaneous) Recognized by adipose tissue.

22. Question What are some of the appendages of the skin?

23. The Skin • Appendages of the skin • Hair • Soft hair of fetus and newborn called lanugo • Hair growth requires epidermal tube-like structure called hair follicle • Hair growth begins from hair papilla

24. The Skin • Appendages of the skin • Hair • Hair root lies hidden in follicle; visible part of hair called shaft • Alopecia hair loss • Arrector pili—specialized smooth muscle that produces “goose pimples” and causes hair to stand up straight

26. The Skin • Nails • Produced by epidermal cells over terminal ends of fingers and toes • Visible part called nail body • Root lies in a groove and is hidden by cuticle • Crescent-shaped area nearest root called lunula • Nail bed may change color with change in blood flow

29. The Skin • Skin glands • Types • Sweat or sudoriferous • Sebaceous

30. The Skin • Skin glands • Sweat or sudoriferous glands • Types • Eccrine sweat gland • Most numerous, important, and widespread of the sweat gland • Produce perspiration or sweat, which flows out through pores on skin surface • Function throughout life and assist in body heat regulation

31. The Skin • Skin glands • Sweat or sudoriferous glands • Types • Apocrine sweat gland • Found primarily in axilla and around genitalia • Secrete a thicker, milky secretion quite different from eccrine perspiration • Breakdown of secretion by skin bacteria produces odor

32. The Skin • Skin glands • Sweat or sudoriferous glands • Types • Sebaceous gland • Secrete oil or sebum for hair and skin • Level of secretion increases during adolescence • Amount of secretion regulated by sex hormones • Sebum in sebaceous gland ducts may darken to form a blackhead • Acne vulgaris inflammation of sebaceous gland ducts

33. Dermis Sweat gland Sebaceous gland Arrector pili muscle Blood vessels

34. The Skin • Appendages of the skin • Receptors • Specialized nerve endings—make it possible for skin to act as a sense organ • Meissner’s corpuscle—capable of detecting light touch • Pacinian corpuscle—capable of detecting pressure

35. Quick Quiz Which layer does not have a blood supply?

36. Quick Quiz Which layer has the pigment cells?

37. Quick Quiz What is that pigment called?

38. Quick Quiz Which layer has the fatty tissue?

39. Quick Quiz Which part of the epidermis is undergoing mitosis all the time?

40. Case Study Katie is a 15-year-old girl who is very upset because of the pimples on her face. She cannot understand why her little sister Kimberly, who is 7, doesn’t have acne.

41. Question What explanation can you give Katie concerning her skin? A. In several years Kimberly also will have acne. B. Acne is present most likely because she doesn’t wash her face. C. Acne is an allergic reaction to certain creams used on the face. D. Acne in adolescence is a result of overactive sebaceous glands.

42. Question Katie is embarrassed because of the pimples on her face. Her mother has decided to seek medical attention. What sort of doctor will she probably see? A. dermatologist B. cosmetic specialist C. plastic surgeon D. pediatrician

43. Question Which of the following statements about hair follicles is true? A. Arrectorpili muscles are associated with them. B. Sudoriferous glands empty into them. C. They arise directly from the epidermis layer of skin. D. All of the above.

44. Burns • Classification of burns • First-degree (partial-thickness) burns—only the surface layers of epidermis involved • Second-degree (partial-thickness) burns—involve the deep epidermal layers and always cause injury to the upper layers of the dermis • Third-degree (full-thickness) burns—characterized by complete destruction of the epidermis and dermis and subcutaneous tissues.

45. THE SKIN • Burns • Treatment and recovery or survival depend on total area involved and severity or depth of the burn • Body surface area is estimated using the “rule of nines” (Figure 5-8) in adults • Body is divided into 11 areas of 9% each • Additional 1% located around genitals

46. Burns • First-degree (partial-thickness) burns—only surface layers of epidermis involved • Second-degree (partial-thickness) burns—involve the deep epidermal layers and always cause injury to the upper layers of the dermis

49. Burns • Third-degree (full-thickness) burns (Figure 6-14) characterized by complete destruction of the epidermis, dermis, and subcutaneous tissue • May involve underlying muscle and bone (fourth-degree) • Lesion is insensitive to pain because of destruction of nerve endings immediately after injury—intense pain is soon experienced