Chapter Outline

Chapter 12

Suggested Lecture Outline

I. INTRODUCTION

A. The nervous system, along with the endocrine system, helps to keep controlled conditions within limits that maintain health and helps to maintain homeostasis.

B. The nervous system is responsible for all our behaviors, memories, and movements.

C. The branch of medical science that deals with the normal functioning and disorders of the nervous system is called neurology.

II. OVERVIEW OF THE NERVOUS SYSTEM

A. Structures of the Nervous System

1. The nervous system is made up of the brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexus, and sensory receptors (Figure 12.1).

2. The brain is housed within the skull.

3. Twelve pairs of cranial nerves emerge from the base of the brain through foramina of the skull.

4. A nerve is a bundle of hundreds or thousands of axons, each of which courses along a defined path and serves a specific region of the body.

5. The spinal cord connects to the brain through the foramen magnum of the skull and is encircled by the bones of the vertebral column.

6. Thirty-one pairs of spinal nerves emerge from the spinal cord, each serving a specific region of the body.

7. Ganglia, located outside the brain and spinal cord, are small masses of nervous tissue, containing primarily cell bodies of neurons.

8. Enteric plexuses help regulate the digestive system.

9. Sensory receptors are either parts of neurons or specialized cells that monitor changes in the internal or external environment.

B. Functions of the Nervous Systems

1. The sensory function of the nervous system is to sense changes in the internal and external environment through sensory receptors. Sensory (afferent) neurons serve this function.

2. The integrative function is to analyze the sensory information, store some aspects, and make decisions regarding appropriate behaviors. Association or...