Unit One, Lesson Three: Brain and Behavior

Introduction

In this lesson, you will learn about how our brains and endocrine systems affect our behavior. It is also important to have an understanding of these concepts because they will appear on the Advanced Placement Exam.

Objectives

By the end of this lesson, you should be able to

• explain the relationship between the nervous system and endocrine system;
• trace the effect of glands on the body and behavior; and
• relate handedness, brain dominance, and speech, and differentiate the abilities of the two hemispheres of the cerebral cortex.

Click Key Terms for a list of important terms and concepts for this lesson. You should know all the key terms listed in the chapter reading for this lesson, however.

Questions to Think About

As you move through this lesson, consider these questions:

• How does a nerve impulse (action potential) occur and how is it an all-or-nothing event?
• Describe the effect of myelin on the speed of the nerve impulse.
• Explain how and why our brains are "split."
• What are the subparts of the human nervous system?
• Describe the actions of hormones on the body.
  

Related Resources

• Sacks, O. 1985. The Man Who Mistook His Wife for a Hat and Other Clinical Tales. New York: HarperCollins Publishers, Inc., 1985.
• Scientific American, September 1979. (This entire issue is devoted to the brain.)
• Web site: Society for Neuroscience
  http://www.sfn.org/

Reading Assignment

Here you will learn about physiological factors related to human behavior. This area of psychology is important, and its importance has increased in the field within the last ten years because of various breakthroughs in understanding the brain and the biological factors that affect emotions, cognition, and behaviors.

In this Reading Assignment, you'll read the following selection from your textbook, Essentials of Psychology (unless otherwise indicated, read the entire chapter):

10^th edition: chapter 2, "The Brain and Behavior"

While this activity is not scored, it's important that you complete the reading so you can complete the other activities in this lesson that are based on the reading.

To complete the Reading Assignment, I recommend you do the following.

• Open, print, and read the Study Guide. Think about the questions posed on the Study Guide as you read.
• Open, print, and read the Study Guide Answers to compare with your answers on the Study Guide.
• Keep the Study Guide and Study Guide Answers in your course notebook to refer to as you work through the course.

Learn About Neurons

In this How It Works, you'll see how neurons function to carry and process information, activate muscles and glands, and activate the most basic process of human functioning.

Parts of the Neuron

Neurons are nerve cells. There are about 100 billion neurons in your brain. Obviously, they don't all look exactly like this image, but most of them have these four basic parts. Place your cursor on the terms in the image to learn more about the parts of a neuron.

Nerve Impulses

Messages called nerve impulses are transmitted from the cell body down the axon. When a nerve impulse is triggered near the cell body (soma), a wave of activity travels down the axon. This activity is based on an electrical charge. When the electrical charge reaches a threshold level above the resting level, the action potential is triggered. Notice how the action potential proceeds from the cell body (soma) down the axon.

The Synapse

The synapse is the microscopic space between neurons where messages pass from one neuron to the next neuron. While the nerve impulse is electrical, what happens at the synapse is chemical.

Place your cursor over the terms in the graphic to see their definitions.

 

When the impulse reaches the axon terminals, it causes the release of chemicals called neurotransmitters. Neurotransmitters have the ability to alter the activity of other neurons. When they are released by the neuron sending the message they go into the gap (or synapse). Click on the play button to see how neurotransmitters pass between neurons.

The receiving neuron has receptors that can "grab on" to the neurotransmitters. If the neurotransmitters are excitatory, it may cause the next neuron to fire a nerve impulse. If they are inhibitory, they may prevent the next neuron from firing.

Many drugs mimic the jobs of various neurotransmitters, others work to prevent the neurotransmitters from being reabsorbed too quickly. For example, Prozac, a common anti-depressant drug, is believed to work by preventing too much serotonin (a neurotransmitter) from being absorbed before it can pass the message on to the next neuron.

Discuss It

What is Interesting? What is Confusing?

Post your questions and insights regarding this lesson to the discussion group. For example, you could post a question on the material from the exploration or the reading, or point out a recommended resource that helped you understand the materials.

Participating in the discussion will allow you to interact with your virtual classmates and help you perform well on the upcoming unit quiz.

Scoring

This activity is worth 5 points. You will receive 3 points for your initial posting and 2 points for your second posting.

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