An Important Process

Interest Grabber Section 35-1 An Important Process • While walking along a dusty path, you begin to cough. As you continue your walk, a small insect comes flying toward you. You blink and then duck so that it misses you. These actions are just a few examples of homeostasis. Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in their external environments. • 1. List three other examples of homeostasis that occur in organisms. • 2. Why is homeostasis important to an organism?

Section Outline Section 35-1 • 35–1 Human Body Systems A. Organization of the Body 1. Cells 2. Tissues 3. Organs 4. Organ Systems B. Maintaining Homeostasis 1. A Nonliving Example 2. In the Body

Examples of Feedback Inhibition Section 35-1 Thermostat senses temperature change and switches off heating system Room temperature increases Room temperature decreases Thermostat senses temperature change and switches on heating system

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part 2 Section 35-1 Respiratory System Digestive System Excretory System Endocrine System Reproductive System Lymphatic/Immune Systems

Interest Grabber Section 35-2 You’ve Got a Lot of Nerve! • The nervous system controls and coordinates functions throughout the body. The nervous system is one of the body’s communication systems. Without communication, parts of the body could not work together smoothly.

Interest Grabber continued Section 35-2 • 1. Think about tying the shoelace of a sneaker. Construct a flowchart that shows what happens between your eyes and your brain, and between your brain and your hands, when you tie a bow in the shoelace. • 2. How would the communications be different if you tried to tie the shoelace with your eyes closed?

Section Outline Section 35-2 • 35–2 The Nervous System A. Neurons B. The Nerve Impulse 1. The Resting Neuron 2. The Moving Impulse 3. Threshold C. The Synapse

Nucleus Axon terminals Cell body Myelin sheath Axon Nodes Dendrites A Neuron Section 35-2

Figure 35-6 Resting Potential Section 35-2

Figure 35-7 An Impulse Section 35-2

Figure 35-8 The Synapse Section 35-2 Direction of Impulse Dendrite of adjacent neuron Axon Receptor Vesicle Axon terminal Synaptic cleft Neurotransmitter

Interest Grabber Section 35-3 Brainiac • Imagine that you are a computer systems engineer and your job is to design a computer that can perform all the functions of a human brain. • 1. Which brainlike functions can already be performed by computers? • 2. Which brainlike functions cannot be performed by computers? • 3. How successful do you think you (or anyone) could be in designing a computer that can perform all the functions of the human brain? Explain your answer.

Section Outline Section 35-3 • 35–3 Divisions of the Nervous System A. The Central Nervous System B. The Brain 1. The Cerebrum 2. The Cerebellum 3. The Brain Stem 4. The Thalamus and Hypothalamus C. The Spinal Cord D. The Peripheral Nervous System 1. The Somatic Nervous System 2. The Autonomic Nervous System

Central nervous system Peripheral nervous system Sensory nerves Motor nerves Somatic nervous system Autonomic nervous system Parasympathetic nervous system Sympathetic nervous system Concept Map Section 35-3 The Nervous System is divided into which consists of that make up which is divided into

Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Pituitary gland Pons Medulla oblongata Spinal cord Figure 35-9 The Brain Section 35-3

Gray matter Central canal Spinal nerve White matter Meninges Cross Section of the Spinal Cord Section 35-3

Interest Grabber Section 35-4 Taking It All In • Your senses—sight, hearing, smell, touch, taste—are constantly receiving information about your environment. Even if you are not thinking about it, your body is sensing and responding to conditions around you, such as the temperature of the room. • 1. List ten things you observe about the room you are in. • 2. Next to each observation, write the sense that you used to make that observation. • 3. What sense did you use most?

Section Outline Section 35-4 • 35–4 The Senses A. Vision B. Hearing and Balance 1. Hearing 2. Balance C. Smell and Taste D. Touch and Related Senses

Olfactory (smell) bulb Taste sensory area Olfactory nerve Thalamus Cerebral cortex Smell receptor Nasal cavity Smell sensory area Taste bud Taste pore Taste receptor Sensory nerve fibers The Senses of Smell and Taste Section 35-4

Vitreous humor Muscle Lens Fovea Aqueous humor Cornea Pupil Optic nerve Iris Blood vessels Ligaments Retina Choroid Sclera Figure 35-14 The Eye Section 35-4

Oval window Stirrup Anvil Semicircular canals Hammer Cochlear nerve Cochlea Bone Auditory canal Tympanum Round window Eustachian tube Figure 35-15 The Ear Section 35-4

Interest Grabber Section 35-5 Poster Designer • Imagine that you are working with a local community group to help stop drug abuse among teenagers. Your first assignment is to design a drug abuse awareness poster. • 1. Complete a brief sketch of your idea on a sheet of paper. What effects of drugs does your poster depict? • 2. Why do you think teenagers will pay attention to your poster?

Section Outline Section 35-5 • 35–5 Drugs and the Nervous System A. Drugs That Affect the Synapse 1. Stimulants 2. Depressants 3. Cocaine 4. Opiates 5. Marijuana 6. Alcohol 7. Alcohol and Disease B. Drug Abuse

Commonly Abused Drugs Section 35-5 Used to increase alertness, relieve fatigue Used to relieve anxiety, irritability, tension Used to relieve pain Stimulants Depressants Opiates Amphetamines Barbiturates Tranquilizers Morphine Codeine Increase heart and respiratory rates; elevate blood pressure; dilate pupils; decrease appetite Slow down the actions of the central nervous system; small amounts cause calmness and relaxation; larger amounts cause slurred speech and impaired judgement Act as a depressant; cause drowsiness, restlessness, nausea Drug Type Medical Use Examples Effects on the body

Videos Video Contents • Click a hyperlink to choose a video. • Action Potential • Synaptic Transmission

Video 1 Action Potential Video 1 • Click the image to play the video segment.

Video 2 Synaptic Transmission Video 2 • Click the image to play the video segment.

Go Online Internet • The latest discoveries in the nervous and immune systems • Interactive test • Articles on the human body • For links on the nervous system, go to www.SciLinks.org and enter the Web Code as follows: cbn-0352. • For links on the human brain, go to www.SciLinks.org and enter the Web Code as follows: cbn-0353. • For links on the senses, go to www.SciLinks.org and enter the Web Code as follows: cbn-0354. • For links on drugs and drug abuse, go to www.SciLinks.org and enter the Web Code as follows: cbn-0355.

Interest Grabber Answers • 1. List three other examples of homeostasis that occur in organisms. • Accept all reasonable student examples that show an understanding of homeostasis. • 2. Why is homeostasis important to an organism? • Homeostasis allows an organism to remain in balance with its environment. If homeostasis is not maintained, it can harm the organism or result in the death of the organism. Section 1 Answers

Interest Grabber Answers Section 2 Answers • 1. Think about tying the shoelace of a sneaker. Construct a flowchart that shows what happens between your eyes and your brain, and between your brain and your hands, when you tie a bow in the shoelace. • Students’ flowcharts should include: The eyes inform the brain about the position of the hands and the shoelace; the brain signals the hands how to move to begin to tie the bow; and so on. • 2. How would the communications be different if you tried to tie the shoelace with your eyes closed? • All information about the position of the shoelace would have to come from the hands as they feel and manipulate the shoelace.

Interest Grabber Answers • 1. Which brainlike functions can already be performed by computers? • Computation and data sorting • 2. Which brainlike functions cannot be performed by computers? • Original thought and perception of emotions • 3. How successful do you think you (or anyone) could be in designing a computer that can perform all the functions of the human brain? Explain your answer. • Students will likely say not successful, because a computer cannot be designed to feel emotions. Section 3 Answers

Interest Grabber Answers • 1. List ten things you observe about the room you are in. • Students will likely describe the shape and color of the room, what is written on the chalkboard, whether doors or windows are open, how bright the lighting is, the temperature, ticking of a clock, rustling of papers, and so on. • 2. Next to each observation, write the sense that you used to make that observation. • Most observations are likely to be based on sight and hearing. If students list only visual observations, have them make some observations with their eyes closed. • 3. What sense did you use most? • Possible answer: sight Section 4 Answers

Interest Grabber Answers • 1. Complete a brief sketch of your idea on a sheet of paper. What effects of drugs does your poster depict? • Possible answer: negative effects on the brain, which may result in various types of injuries or death. • 2. Why do you think teenagers will pay attention to your poster? • Answers will depend on the design of the poster. Teenagers may respond to concern about loss of mental or athletic ability or concern about possible injuries. Section 5 Answers

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An Important Process