1. Chapter 15 The Nervous System 15.1 How the Nervous System Works 15.2 Divisions of the Nervous System 15.3 Sight and Hearing 15.4 Smell, Taste, and Touch 15.5 Alcohol and Other Drugs Table of Contents Chapter Preview 15.1 How the Nervous System Works 15.2 Divisions of the Nervous System 15.3 Sight and Hearing 15.4 Smell, Taste, and Touch 15.5 Alcohol and Other Drugs

2. Chapter 15 The Nervous System Chapter Preview Questions 1. Which part of the skeletal system protects the brain? a. spine b. pelvis c. skull d. joint

3. Chapter 15 The Nervous System Chapter Preview Questions 1. Which part of the skeletal system protects the brain? a. spine b. pelvis c. skull d. joint

4. Chapter 15 The Nervous System Chapter Preview Questions 2. Which muscles can you control voluntarily? a. heart muscles b. leg muscles c. diaphragm d. stomach muscles

5. Chapter 15 The Nervous System Chapter Preview Questions 2. Which muscles can you control voluntarily? a. heart muscles b. leg muscles c. diaphragm d. stomach muscles

6. Chapter 15 The Nervous System Chapter Preview Questions 3. What is the smallest unit of any body system? a. structure b. organ c. tissue d. cell

7. Chapter 15 The Nervous System Chapter Preview Questions 3. What is the smallest unit of any body system? a. structure b. organ c. tissue d. cell

8. Chapter 15 The Nervous System Chapter Preview Questions 4. What is the eye designed to receive from the environment? a. light rays b. vibrations c. lenses d. motion

9. Chapter 15 The Nervous System Chapter Preview Questions 4. What is the eye designed to receive from the environment? a. light rays b. vibrations c. lenses d. motion

10. Chapter 15 The Nervous System You smell a delicious aroma. You walk into the kitchen and see a bag of popcorn in the microwave. You hear some kernels still popping. Then you think to yourself, “Snack time!” Which body systems enabled you to smell, walk, see, hear, and think? How did each system play a part in your response? How do organs and other structures enable the nervous system to function?

11. Chapter 15 The Nervous System Suffixes SuffixMeaning of SuffixExample and Meaning of Example A person or thing that -ant Pollutant Something that pollutes or makes dirty

12. Chapter 15 The Nervous System Suffixes SuffixMeaning of SuffixExample and Meaning of Example Action or practice of -ism Criticism Action of judging the value of something

13. Chapter 15 The Nervous System SuffixMeaning of SuffixExample and Meaning of Example Condition of; state of -ness Sickness Condition of being sick Suffixes

14. Chapter 15 The Nervous System SuffixMeaning of SuffixExample and Meaning of Example Having; full of -ous Disastrous Full of disaster Suffixes

15. Chapter 15 The Nervous System Apply It! 1. What is the suffix in the word nearsightedness? What does the suffix mean? -ness; it means the condition of being nearsighted 2. The word stimulate means “to increase activity. ” Predict the meaning of stimulant. Revise your definition as needed after you read Section 5. Sample answer: It means something that increases activity. Revised definition: A stimulant is a drug that speeds up body processes.

16. Chapter 15 The Nervous System End of Chapter Preview

17. Chapter 15 The Nervous System Section 1: How the Nervous System Works What are the functions of the nervous system? What is the structure of a neuron and what kinds of neurons are found in the body? How do nerve impulses travel from one neuron to another?

18. Chapter 15 The Nervous System The Neuron A neuron has a large cell body that contains the nucleus, threadlike extensions called dendrites, and an axon.

19. Chapter 15 The Nervous System How a Nerve Impulse Travels For a nerve impulse to be carried along at a synapse, it must cross the gap between the axon and the next structure. The axon tips release chemicals that carry the impulse across the gap.

20. Chapter 15 The Nervous System More on Nerve Impulses Click the PHSchool.com button for an activity about nerve impulses.

21. Chapter 15 The Nervous System Nervous System Click the Video button to watch a movie about the nervous system.

22. Chapter 15 The Nervous System End of Section: How the Nervous System Works

23. Chapter 15 The Nervous System Section 2: Divisions of the Nervous System What are the structures and functions of the central nervous system? What are the structures and functions of the peripheral nervous system? What is a reflex? What are two ways in which the nervous system can be injured?

24. Chapter 15 The Nervous System Central Nervous System The central nervous system is the control center of the body. It includes the brain and spinal cord.

25. Chapter 15 The Nervous System Nervous System Activity Click the Active Art button to open a browser window and access Active Art about nervous system.

26. Chapter 15 The Nervous System The Brain There are three main regions of the brain that receive and process information. These are the cerebrum, the cerebellum, and the brain stem.

27. Chapter 15 The Nervous System Peripheral Nervous System The peripheral nervous system consists of a network of nerves that branch out from the central nervous system and connect it to the rest of the body. The peripheral nervous system is involved in both involuntary and voluntary actions.

28. Chapter 15 The Nervous System Reflexes A reflex is an automatic response that occurs very rapidly and without conscious control.

29. Chapter 15 The Nervous System Reflexes A reflex is an automatic response that occurs very rapidly and without conscious control.

30. Chapter 15 The Nervous System End of Section: Divisions of the Nervous System

31. Chapter 15 The Nervous System Section 3: Sight and Hearing How do your eyes enable you to see? How do you hear and maintain your sense of balance?

32. Chapter 15 The Nervous System Vision You eyes respond to the stimulus of light. They convert that stimulus into impulses that your brain interprets, enabling you to see.

33. Chapter 15 The Nervous System Virtual Dissection of the Eye Activity Click the Active Art button to open a browser window and access Active Art about a virtual dissection of the eye.

34. Chapter 15 The Nervous System Vision Light coming from an object enters your eye and is focused by the lens. The light produces an upside-down image on your retina. Receptors in your retina then send impulses to your cerebrum, which turns the image right-side up.

35. Chapter 15 The Nervous System Hearing and Balance Your ears are the sense organs that respond to the stimulus of sound. Ears convert the sound to nerve impulses that your brain interprets.

36. Chapter 15 The Nervous System Sound Intensity Sound intensity, or loudness, is measured in units called decibels. The threshold of hearing for the human ear is 0 decibels. For every 10-decibel increase, the sound intensity increases ten times. Thus, a 20-decibel sound is ten times more intense than a 10-decibel sound. A 30-decibel sound is 100 times more intense than a 10- decibel sound. Sound levels for several sound sources are shown in the bar graph.

37. Chapter 15 The Nervous System Sound Intensity Decibels, or sound level; type of sound Reading Graphs: What unit of measure is represented on the y-axis? What is represented on the x- axis?

38. Chapter 15 The Nervous System Sound Intensity 20dB; 60dB; 120dB Interpreting Data: What is the sound intensity in decibels of a whisper? Normal talking? A rock concert?

39. Chapter 15 The Nervous System Sound Intensity 20 dB vs. 60 dB, which is 10,000 times more intense Calculating: How much more intense is normal talking than a whisper? Explain.

40. Chapter 15 The Nervous System Sound Intensity Rock concert; jet plane taking off Predicting: Based on the graph, what types of sound could be painful if you were exposed to them?

41. Chapter 15 The Nervous System End of Section: Sight and Hearing

42. Chapter 15 The Nervous System Section 4: Smell, Taste, and Touch What are the functions of the nervous system? What is the structure of a neuron and what kinds of neurons are found in the body? How do nerve impulses travel from one neuron to another?.

43. Chapter 15 The Nervous System Smell and Taste The senses of smell and taste work closely together. Both depend on chemicals in food or in the air. The chemicals trigger responses in receptors in the nose and mouth.

44. Chapter 15 The Nervous System Links on the Senses Click the SciLinks button for links on the senses

45. Chapter 15 The Nervous System End of Section: Smell, Taste, and Touch

46. Chapter 15 The Nervous System Section 5: Alcohol and Other Drugs What are the functions of the nervous system? What is the structure of a neuron and what kinds of neurons are found in the body? How do nerve impulses travel from one neuron to another?

47. Chapter 15 The Nervous System Drug Abuse Drug abuse can have serious consequences. However, there are ways to tell if someone is abusing drugs and ways to help that person.

48. Chapter 15 The Nervous System Alcohol Alcohol is a drug found in many beverages, including beer, wine, cocktails, and hard liquor. Alcohol is a powerful depressant and affects every system of the body.

49. Chapter 15 The Nervous System Links on Drug Addiction Click the SciLinks button for links on drug addiction.

50. Chapter 15 The Nervous System End of Section: Alcohol and Other Drugs

51. Chapter 15 The Nervous System QuickTake Quiz Click to start quiz.