1. Copyright 2010, John Wiley & Sons, Inc. Chapter 5 The Integumentary System

2. Copyright 2010, John Wiley & Sons, Inc. End of Chapter 5 Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein.

3. Copyright 2010, John Wiley & Sons, Inc. Integumentary System The body’s covering Includes: skin, nails, and hairs Skin: cutaneous membrane

4. Copyright 2010, John Wiley & Sons, Inc. Structure Two main parts  Epidermis - surface epithelial layer  Dermis - deeper connective tissue layer Subcutaneous (subQ) layer or hypodermis lies deep to dermis; is not part of the skin

5. Copyright 2010, John Wiley & Sons, Inc. Integumentary System

6. Copyright 2010, John Wiley & Sons, Inc. Epidermis Keratinized stratified squamous epithelium Cell types (4):  Keratinocytes  Melanocytes  Langerhans cells  Merkel cells

7. Copyright 2010, John Wiley & Sons, Inc. Epidermal Cells Keratinocytes  90% of epidermal cells  4-5 layers  Produce keratin  Protects skin  Waterproofs skin

8. Copyright 2010, John Wiley & Sons, Inc. Epidermal Cells Melanocytes  Produce melanin that gives color to skin, hairs  Transfer pigment to keratinocytes  Make up 8% of epidermal cells

9. Copyright 2010, John Wiley & Sons, Inc. Epidermal Cells Langerhans cells  Immune response Merkel cells  Sense of touch  Consist of tactile disc and neuron for touch sensation

10. Copyright 2010, John Wiley & Sons, Inc. Epidermal Layers Four Layers (strata)  Stratum basale Includes stem cells; new cells arise here  Stratum spinosum: 8-10 cell layer Cells beginning to look flattened  Stratum granulosum makes keratin Losing cell organelles and nuclei Have waterproofing lipid  Stratum corneum: flattened dead cells Cells here consist mostly of keratin. Cells here are shed and replaced from below.

11. Copyright 2010, John Wiley & Sons, Inc. Skin Color Melanin: dark color  Darkness depends on amount of melanin produced.  Provides some protection against UV rays Carotene: yellow orange  In stratum corneum and adipose layers- Hemoglobin in blood: pink-red  Depends on blood flow

12. Copyright 2010, John Wiley & Sons, Inc. Accessory Structures Hair Skin glands Nails

13. Copyright 2010, John Wiley & Sons, Inc. Hair Found on most skin surfaces  Not on palmar surfaces of hand and fingers or plantar surfaces of feet Made of fused keratinized cells Consists of shaft and root Surrounded by hair follicle  Base is bulb which includes growing matrix producing cells Nerves in hair root plexuses Muscle that pulls on hair: arrector pili Causes hair to stand on end

14. Copyright 2010, John Wiley & Sons, Inc. Hair

15. Copyright 2010, John Wiley & Sons, Inc. Glands Sebaceous gland: secrete oily sebum  Connected to hair follicles; keeps hair from drying out Sudoriferous (sweat) gland  Eccrine sweat gland  Wide distribution- thermoregulation  Apocrine sweat gland  Axilla, groin, areolae, beard  Contain other cell material Ceruminous (wax) gland  Wax combines with sebum to produce earwax

16. Copyright 2010, John Wiley & Sons, Inc. Nails Plates of packed hard dead keratinized cells Nail body: major visible portion Free edge: part extending past finger or toe Root: cells deep to here (in nail matrix) form new nail cells

17. Copyright 2010, John Wiley & Sons, Inc. Nails

18. Copyright 2010, John Wiley & Sons, Inc. Nails

19. Copyright 2010, John Wiley & Sons, Inc. Functions Temperature regulation Protection Sensory reception Excretion and absorption: small amounts Vitamin D synthesis

20. Copyright 2010, John Wiley & Sons, Inc. Aging Adolescence: can develop acne Most effects in dermis, with visible signs of aging by about age 40. These include:  Loss of collagen fibers  Loss of elasticity  Loss of immune responses  Decreased melanocyte functions: gray hair, skin blotches  Thinning of skin and hairs Anti-aging treatments