Module 1

1. Module 1

1.3. Lesson 1

Lesson 1

Module 1—The Nervous System

Lesson 1—Structure and Organization of the Nervous System

Get Focused

In the Big Picture you imagined being in a room full of people and trying to get the nerve to approach a student who is new to your school, and hopefully make a new friend. You started to breathe faster and your heart rate went up as you approached her to say “hi.” It took some effort to calm yourself down. In this situation, you could not control your breathing and heart rate, but you did have control of your legs and the direction in which they were taking you.

nervous system: an elaborate communication system that receives input; processes, integrates, and stores information; and triggers muscle contraction or glandular secretion

homeostasis: the tendency of the body to maintain a state of equilibrium or a stable internal environment

Can you imagine being able to control your breathing and heart rate like you control your legs? This is where the nervous system gets divided into the unconscious, or involuntary, section and the conscious, or voluntary, part. Processes vital to life, like breathing, are controlled unconsciously. Just try to see how long you can hold your breath! In this lesson you will explore mechanisms that increase your breathing rate and slow it down, returning you to a normal or balanced state. This state is called homeostasis.

Controlling your skeletal muscles, such as your legs, is a conscious or voluntary act. In Lesson 1 you will discover the part of the nervous system responsible for voluntary control, and you will see what happens when the pathways in your nervous system are interrupted.

This photograph shows a silver two-door car that has been involved in a collision. The front fender and door on the driver’s side is badly damaged and the airbag has deployed.

Injuries, such as paralysis or the loss of a limb, can interrupt communication in the conscious part of your nervous system. However, someone seriously injured in a car accident may learn how to walk again through the re-establishment of communication in the conscious nervous system. This may be achieved through a combination of physiotherapy, surgery, and other technologies developed to enhance or repair communication pathways in the nervous system.

In this lesson you will investigate the following focusing questions:

How is the nervous system organized, and how do its parts communicate with each other?
What interrupts the normal communication mechanisms of the sympathetic and parasympathetic parts of the nervous system?

sympathetic nervous system: the division of the autonomic nervous system that activates the body to cope with some stressor, such as danger, excitement, or fear; sometimes referred to as the fight, fright, and flight subdivision

parasympathetic nervous system: the division of the autonomic nervous system that oversees digestion, elimination, and glandular function; often works opposite the sympathetic nervous system to bring the body back to normal

Module 1: Lesson 1 Assignment

Your teacher-marked Module 1: Lesson 1 Assignment requires you to submit a response to the following:

Part 1—Response to Video
Part 2—Reflect and Connect

Download a copy of the Module 1: Lesson 1 Assignment to your computer now. You will receive further instructions about how to complete this assignment later in the lesson.

The other questions in this lesson are not marked by the teacher; however, you should still answer these questions. The Self-Check and Try This questions are placed in this lesson to help you review important information and build key concepts that may be applied in future lessons.

After a discussion with your teacher, you must decide what to do with the questions that are not part of your assignment. For example, you may decide to submit to your teacher the responses to Try This questions that are not marked. You should record the answers to all the questions in this lesson and place those answers in your course folder.

During this lesson you will begin the Module Assessment project that you were introduced to in the Big Picture. This will begin with initial research into Alzheimer’s disease. This research will be stored in your course folder.