Chapter 40

1. Why is the skin so important? 2. Name some of the things that it does. 3. How many layers has it? Describe each. 4. What glands are found in the skin? 5. What is sweat, or perspiration, and from what does it come? 6. Why should clothing be porous? 7. Why should clothing be frequently washed? 8. Describe a hair gland and its muscles. 9. Describe the process of "nail-making." 10. Is there any process like this among the lower animals? 11. Why do we need nails? 12. What causes the white crescent on the nail? 13. Explain how the skin is a heat regulator. 14. What is the "normal temperature" of the body? 15. How does perspiring affect the heat of the body? 16. What are the "nerve buds" or "bulbs"? 17. Name four things that they do.