1. TODAY  Outline chapter 5  Test back  Corrections tonight after school, tomorrow at 7:00 am  Outline p. 100-105 due tomorrow  Project: building day on Wednesday  Due on Friday  Tuesday: finish notes  Wednesday: build models  Thursday: Review page, some build time  Friday: notes, microscope if time

2. { Chapter 5: Integumentary System

3. Objectives  List functions of skin  Explain role of skin in temperature regulation  Describe layers of skin and characteristics  Explain factors that affect skin color  Describe accessory organs of skin

4. Functions  Protection  Temperature Regulation  Vitamin D  Sensory  Excretion

5. Integumentary System  Consists of skin and accessory organs  Skin is 2 regions:  Dermis  epidermis  A fatty layer lies deep (hypodermis)  Hair Follicles  Skin Glands  Nails Skin is the body’s outer covering and its largest organ.

6. Epidermis Dermis Hypodermis Or subcutaneous Structure of Skin

7. Epidermis  Stratified Squamous Epithelium (tissue)  Keratinized: keratin is a tough protein

8. Keratinized: By the time cells reach surface, little more than keratin filled sacs Desquamification : shedding of outermost layer of a tissue

9. Epidermis  No direct blood supply  Nutrients must diffuse into the epidermis Four types of cells Keratinocytes – deepest, produce keratin Melanocytes - make dark skin pigment melanin Merkel cells – associated with sensory nerve endings Langerhans cells – macrophage-like dendritic cells

10. Review 1. The functions of the skin include all of the following except: a. Taking in nutrients b. Preventing entry of microorganisms c. Retarding water loss d. Regulating body temperature

11. Review 1. Which layer of the Integumentary System is the foundation for the skin? a. Epidermis b. Hypodermis c. Dermis d. Stratum Corneum

12. Review 1. Which of the following is NOT considered an accessory organ of the Integumentary System? a. nails b. hair c. arteries d. glands

13. Review 1. Which of the following cell types is responsible for sensory in the epidermis? a. Langerhans b. Keratinocytes c. Melanocytes d. Merkel

14. Epidermis: most superficial

15.  Stratum Corneum:  Many layers of dead cells  keratin, Moisture lock  Stratum Lucidum:  Stratum Granulosum:  Statum Spinosum:  Stratum Basale:

16.  Stratum Corneum:  Stratum Lucidum:  Protect from UV  Thick layer  Only in frequently used areas  Stratum Granulosum:  Statum Spinosum:  Stratum Basale:

17.  Stratum Corneum:  Stratum Lucidum:  Stratum Granulosum:  Thin middle layer  Layers of keratinocytes  Initiate keratinization  Statum Spinosum:  Stratum Basale:

18.  Stratum Corneum:  Stratum Lucidum:  Stratum Granulosum:  Statum Spinosum:  Cells interlock to support skin  Resist tension  Langerhans cells (found more here than other layers)  Stratum Basale:

19.  Stratum Corneum:  Stratum Lucidum:  Stratum Granulosum:  Statum Spinosum:  Stratum Basale:  Single layer of cells  Rest on basement membrane  Cells divide continuously  Youngest cells found here  Melanocytes & Merkel cells here

20. Epithelium: layers (on left) and cell types (on right)