How to Use This Presentation To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show”, or simply press F5 on the top row of your keyboard. To advance to the next slide click the left mouse button once. From the Chapter screen you can click on any section to go directly to that section’s presentation. Blank or “missing” areas of a slide will remain hidden until the left mouse button is clicked. You may exit the slide show at any time by pressing the Esc key Copyright © by Holt, Rinehart and Winston. All rights reserved.

Communication and Control Chapter 25 Section 1: The Nervous System Section 2: Responding to the Environment Section 3: The Endocrine System Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

The Nervous System Section 1 Bellringer List as many functions of the brain as you can. Don’t forget that in addition to controlling your body, your brain is also occupied with thinking. How do you suppose your brain can coordinate all these functions? Record your ideas in your science journal. Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Nervous System Section 1 Objectives Describe the relationship between the central nervous system and the peripheral nervous system. Compare the somatic nervous system with the autonomic nervous system. List one function of each part of the brain. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

The Nervous System Section 1 Two Systems Within a System The CNS and PNS The nervous system has two parts: the central nervous system and the peripheral nervous system. The central nervous system (CNS) is your brain and spinal cord. The CNS processes and responds to all messages coming from the peripheral nervous system. The peripheral nervous system (PNS) is all of the parts of the nervous system except for the brain and the spinal cord. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

The Nervous System Section 1 The Peripheral Nervous System Neuron Structure A neuron is a nerve cell that is specialized to transfer messages in the form of fast-moving electrical energy. The structure of a neuron is shown on the next slide. Information Collection Some neurons are sensory neurons. These neurons gather information about what is happening in and around your body. Delivering Orders Neurons that send impulses from the brain and spinal cord to other systems are called motor neurons. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

A Typical Neuron Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Nervous System Section 1 Nerves What Is a Nerve? The central nervous system is connected to the rest of your body by nerves. A nerve is a collection of axons bundled together with blood vessels and connective tissue. The structure of a nerve is shown on the next slide. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

What Is a Nerve? Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Nervous System Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved. Somatic Nervous System Most of the neurons that are part of the somatic nervous system are under your conscious control. Autonomic Nervous System Autonomic nerves do not need your conscious control. These neurons are part of the autonomic nervous system. The autonomic nervous system controls body functions that you don’t think about, such as digestion and heart rate. Somatic and Autonomic Nervous Systems End of Slide

The Nervous System Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved. The Brain The brain, illustrated on the next slide, is the main control center of the nervous system. The Cerebrum The cerebrum is where you think and where most memories are stored. The Central Nervous System End of Slide

The Nervous System Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved. The Cerebellum The cerebellum processes sensory information from your body, such as from skeletal muscles and joints. The Medulla The medulla controls involuntary processes such as blood pressure, body temperature, heart rate, and involuntary breathing. The Central Nervous System continued End of Slide

The Regions of the Brain Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Nervous System Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved. Route to the Brain The spinal cord is made of neurons and bundles of axons that pass impulses to and from the brain. As you can see on the next slide, the spinal cord is surrounded by protective bones called vertebrae. Spinal Cord Injury A spinal cord injury may block all information to and from the brain. Each year, thousands of people are paralyzed by spinal cord injuries. Many of these injuries happen in car accidents and could be avoided by wearing a seat belt. The Spinal Cord End of Slide

The Spinal Cord Section 1 Copyright © by Holt, Rinehart and Winston. All rights reserved.

Responding to the Environment Section 2 Bellringer List the five senses, and draw the organ associated with each sense as well as an object detected by each sense. Can any of these objects be detected by more than one of the senses? How could it be helpful to use more than one sense to get information about an object? Record your answers in your science journal. Copyright © by Holt, Rinehart and Winston. All rights reserved.

Responding to the Environment Section 2 Objectives List four sensations that are detected by receptors in the skin. Describe how a feedback mechanism works. Describe how light relates to sight. Describe how the senses of hearing, taste, and smell work. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

Responding to the Environment Section 2 Sense of Touch Stimuli and Receptors Touch is what you feel when sensory receptors in the skin are stimulated. Skin has different kinds of receptors. Each kind of receptor responds mainly to one kind of stimulus. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

Responding to the Environment Section 2 Responding to Sensory Messages Reflexes Pain receptors in your skin activate immediate, involuntary actions called reflexes. Reflexes help you move quickly out of the way of danger. Feedback Mechanisms A feedback mechanism is a cycle of events in which information from one step controls or affects a previous step. Your body has many different feedback mechanisms that rely on sensory messages to make sure your body is operating within normal perimeters. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

Responding to the Environment Section 2 Sense of Sight Reacting to Light Your pupil is an opening that lets light enter the eye. The pupil is surrounded by the iris, a ring of muscle. The iris controls the amount of light that enters the eye. Focusing the Light Light travels in straight lines until it passes through the cornea and the lens. Muscles in the eye change the shape of the lens in order to focus light onto the retina. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

Responding to the Environment Section 2 Sense of Hearing Ears Ears are organs specialized for hearing. Each ear has an outer, middle, and inner portion. Sound waves reaching the outer ear are funneled into the middle ear and then the inner ear before being interpreted by the brain. Copyright © by Holt, Rinehart and Winston. All rights reserved. Taste Buds Your tongue is covered with tiny bumps called papillae. Most papillae contain taste buds. Taste buds respond to sweetness, sourness, saltiness, and bitterness. Sense of Taste End of Slide

Responding to the Environment Section 2 Sense of Smell The Nose Knows Receptors for smell are located on olfactory cells in the upper part of your nasal cavity. An olfactory cell is a nerve cell that responds to chemical molecules in the air. You smell something when the receptors react to molecules that have been inhaled. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

The Endocrine System Section 3 Bellringer Unscramble the following words: nalgd meornoh noclotr Try to use each word in a sentence about the endocrine system. Write your answers in your science journal. Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Endocrine System Section 3 Objectives Explain why the endocrine system is important to the body. Identify five glands of the endocrine system, and describe what their hormones do. Describe how feedback mechanisms stop and start hormone release. Name two hormone imbalances. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

The Endocrine System Section 3 Hormones as Chemical Messengers Products of Glands The endocrine system controls body functions by using chemicals that are made by the endocrine glands. A gland is a group of cells that make special chemicals for your body. Chemical messengers made by the endocrine glands are called hormones. Copyright © by Holt, Rinehart and Winston. All rights reserved. Thyroid and Thymus Thyroid hormones control the secretion of growth hormones for normal body growth. Your thymus gland is important to your immune system. Cells called killer T cells grow and mature in the thymus gland. More Endocrine Glands End of Slide

The Endocrine System Section 3 Controlling the Endocrine Glands Feedback Mechanisms Endocrine glands control may feedback mechanisms in the body. Copyright © by Holt, Rinehart and Winston. All rights reserved. Endocrine System Disorders Occasionally, an endocrine gland makes too much or not enough of a hormone. For example, sometimes a child’s pituitary gland doesn’t make enough growth hormone. As a result, the child’s growth is stunted. Hormone Imbalances End of Slide

Communication and Control Chapter 25 Concept Map Copyright © by Holt, Rinehart and Winston. All rights reserved. Use the following terms to complete the concept map on the next slide: brain, neurons, medulla, cerebellum, peripheral nerves, dendrites, spinal cord.

Concept Map Chapter 25 Copyright © by Holt, Rinehart and Winston. All rights reserved.

Concept Map Chapter 25 Copyright © by Holt, Rinehart and Winston. All rights reserved.