The nervous system coordinates all the functions of our bodies, from running, to digesting, to singing, to breathing. For the sake of discussion and study, the nervous system is divided functionally into the somatic nervous system and the autonomic nervous system, or the ANS. These systems are not separate, but rather different components of the nervous system as a whole. The somatic nervous system may be thought of as the conscious nervous system, responsible for functions of which we are aware. It transmits motor signals that cause our voluntary actions and some reflexive actions, and sensory signals about pain, temperature, touch, and position. In addition to these conscious functions, there is an entire set of functions that our nervous system regulates that we rarely, if ever, notice. These unnoticed functions are regulated by the autonomic nervous system and include all of our homeostatic mechanisms. The autonomic nervous system may be thought of as the unconscious nervous system, responsible primarily for maintaining homeostasis. Functions regulated by the autonomic nervous system include heart rate, respiration rate, blood vessel diameter, sweat gland secretion, digestion, etc.
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Fortunately, we do not have to consciously regulate all of our organs' functions; otherwise, a person could die merely from forgetting to breathe. This module will focus on the autonomic nervous system, including its functions and its structure. Many students get confused by the autonomic nervous system, perhaps because it does not follow the patterns of the somatic nervous system or because its structure varies from one part of the body to the next. It may help to remember that the autonomic nervous system innervates all the structures that help maintain homeostasis by whatever means necessary. If you take your time, and go through the autonomic nervous system as a whole until it makes sense, it will definitely pay off many times in the future. |
