Module 1
1. Module 1
1.5. Page 3
Module 1—The Nervous System
Reflect and Connect
You now have the opportunity to reflect on the parts of the nervous system and how they communicate to maintain homeostasis.
Module 1: Lesson 1 Assignment
Retrieve the copy of the Module 1: Lesson 1 Assignment that you saved to your computer earlier in this lesson. Complete Part 2—Reflect and Connect. Save your completed assignment in your course folder. You will receive instructions about when to submit your assignment to your teacher later in this lesson.
Self-Check
SC 2. Define homeostasis. Illustrate your answer by using body temperature as an example.
SC 3. Explain why the nervous system is critical for maintaining homeostasis.
SC 4. Identify what basic neural pathway is involved as you dodge a misdirected tennis ball.
SC 5. How is the autonomic nervous system different from the somatic nervous system?
SC 6. Why do you have to learn how to walk but not how to breathe?
Self-Check Answers
SC 2. Homeostasis is the maintenance of a nearly constant internal environment that fluctuates about a set point, or an ideal point. For example, the set point for body temperature is 37°C. However, the temperature hovers around that value, either below or above by a small amount. When a deviation from the set point occurs, the nervous system will take corrective action; for example, shivering to generate heat in response to feeling cold.
SC 3. The human nervous system is capable of regulating thousands of activities simultaneously. The overall function of the nervous system is to collect information, analyze (sort, integrate, and interpret) the information, and to initiate an appropriate response to maintain a state of dynamic equilibrium or homeostasis. The nervous system accomplishes this function quickly and precisely. Quick action is often needed to get you out of dangerous situations.
SC 4. A sense organ, in this case the eye, detects the ball and the sensory neuron (optic nerve) carries the message to the brain. At this point, an interneuron interprets the information and sends a message via a motor neuron, which causes muscles to act to withdraw (to move the head out of the way of the ball).
SC 5. The somatic nervous system, which takes messages via motor neurons to the skeletal muscles of the body, is controlled by the conscious part of the brain (cerebrum) and causes voluntary (conscious) movements of the muscles. The autonomic nervous system, which is composed of sympathetic and parasympathetic motor neurons, carries messages to cardiac and smooth muscles. This causes an involuntary (not necessarily conscious) contraction of these muscles.
SC 6. A person needs to learn how to contract skeletal muscles (voluntary control by the somatic nervous system). However, one does not need to learn how to contract smooth or cardiac muscle (involuntary control by the autonomic nervous system) or how to carry out reflexes, which are automatic.