Drugs & the Nervous System

Topics: Brain, Nervous system, Neuron Pages: 14 (4253 words) Published: July 1, 2013
Question 1.

a. Develop an outline of the components of the human nervous system, inclusive of the CNS (central nervous system) the somatic system, and both divisions of the autonomic nervous system (ANS). Include in your outline the major distinctions among these systems.

Human Nervous System – Overview

The human nervous system is composed of all nerve tissues in the body. The functions of nerve tissue are to receive stimuli, transmit stimuli to nervous centers, and to initiate response

The nervous system has two distinct parts -- CENTRAL and PERIPHERAL. The central part is made up of the brain and spinal cord. The peripheral part of the nervous system is said to be peripheral because it is outside the central nervous systems. The human nervous system contains approximately 10 billion nerve cells. These neurons are the basic building blocks of the nervous system. Neurons consist of the nerve cell body and various extensions from the cell body. These extensions, or processes, are the dendrites (branches off the cell that receive electrical impulses), the axon (the electrical wiring and conduit tube that conducts impulses), and specialized endings (terminal areas to transfer impulses to receivers on other nerves or muscles).

CENTRAL NERVOUS SYSTEMThe central nervous system is the processing center for the nervous system. It receives information from and sends information to the peripheral nervous system. The main organs of the central nervous system are the brain and spinal cord. The brain processes and interprets sensory information sent from the spinal cord. Both the brain and spinal cord are protected by three layers of connective tissues called the meninges.Spinal CordThe spinal cord is a cylindrical shaped bundle of nerve fibers that is connected to the brain. The spinal cord runs down the center of the protective spinal column extending from the neck to the lower back. Spinal cord nerves transmit information from body organs and external stimuli to the brain and send information from the brain to other areas of the body. The nerves of the spinal cord are grouped into bundles of nerve fibers that travel in two pathways. Ascending nerve tracts carry sensory information from the body to the brain. Descending nerve tracts send information pertaining to motor function from the brain to the rest of the body.Brain The brain is the control center of the body. It consists of three main components: the forebrain, the brainstem, and the hindbrain. The forebrain is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function. The forebrain contains structures such as the thalamus and hypothalamus which are responsible for such functions as motor control, relaying sensory information, and controlling autonomic functions. It also contains the largest part of the brain, the cerebrum. Most of the actual information processing in the brain takes place in the cerebral cortex.

The midbrain and the hindbrain together make up the brainstem. The midbrain is the portion of the brainstem that connects the hindbrain and the forebrain. This region of the brain is involved in auditory and visual responses as well as motor function.

The hindbrain extends from the spinal cord and contains structures such as the pons and cerebellum. These regions assist in maintaining balance and equilibrium, movement coordination, and the conduction of sensory information. The hindbrain also contains the medulla oblongato hich is responsible for controlling such autonomic functions as breathing, heart rate, and digestion.THE PERIPHERAL NERVOUS SYSTEMThe peripheral nervous system includes all nerves not in the brain or spinal cord and connects all parts of the body to the central nervous system. The peripheral (sensory) nervous system receives stimuli, the central nervous system interprets them, and then the...
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