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This chapter describes the skin and its appendages. It explains the structure and function of the layers of skin (dermis and epidermis) and the hair, nails, and sweat glands. This chapter also explains how the skin helps regulate body temperature and how it responds to environmental factors, such as sunlight and injury.
Study of the integumentary system is essential to understanding how the body controls interaction between the internal and external environments.
After you have studied this chapter, you should be able to:
1. Define organ, and name the large organ of the integumentary system. 2. List the general functions of the skin.
3. Describe the structure of the various layers of the skin. 4. Summarize the factors that determine skin color.
5. Describe the accessory organs associated with the skin.
6. Explain the functions of each accessory organ.
7. Explain how the skin functions in regulating body temperature. 8. Describe wound healing.
9.Distinguish amoun the types of burns, including a description of healing with each type. 10. Summarize the life-span changes in the integumentary system.
You have spent the day on the beach in 90(heat. You return to your air-conditioned home and notice that you have several insect bites that you have scratched open. How does the skin help you to adjust to the changes in temperature and prevent a systemic infection?
I. AIDS TO UNDERSTANDING WORDS Define the following word parts.
epi-(upon, after, in addition)
We are now ready to move to the next higher level of organization. We’ve looked at atoms, molecules, and the macromolecules of life. The interactions of the different types of biomolecules make a living cell possible. Molecular interactions vary within cells as a result of the control of DNA in the chromosomes, making the cells differentiate. Groups of cells which have differentiated in the same way form tissues, and in the last chapter, we looked at some of the many kinds of tissues that are found in our body. We are now ready to look at the way the different tissue types work together to form organs that are part of organ systems. An organ consists of (two or more tissues group) working together to (form a organ). By weight, the (skin) is the largest organ of the body. It consists of various tissues and (cells), and forms a strong, environmentally-resistant covering to protect the rest of our bodies. It has many homeostatic functions. Some of the functions include forming (protective cover) and (retards water loss by diffusion ), (regulate body temperature), and maintaining (homeostasis). It is also an active part of our (sensory) and (immune) systems, (removes) wastes and synthesizes (Vitamin D) The integument consists of two layers, an outermost layer of (epidermis ) which is supported by (basement membrane) which is called the (basal lamina). Under the integumentary layers is the (dermis) which fastens the integument to the underlying structures of (adipose tissue) and (subcutaneous layer). Terms to define:
Intradermal (are injected into the skin)
Subcutaneous (are injected into the subcutaneous tissue) Intramuscular (injected into the muscles)
Transdermal (administered on the skin)
Since the epidermis is totally composed of stratified squamous epithelium, it has no blood vessels. In other words, it is (dead). All nutrients pass down a concentration gradient from the region of numerous capillaries found just into the underlying dermal layer. Differences in the amount of nutrients available to epidermal cells result in formation of layers within the epidermis. The cells resting on the...