Chapter 15 - Section 15.1 - Study Guide - Assess Your Learning Outcomes - Page 575: 4

It cannot be said that at any given moment, either the sympathetic or the parasympathetic division of the autonomic nervous system (ANS) is exclusively active because the ANS operates with a continuous balance and interplay between the two divisions. This balance is maintained to varying degrees depending on the specific needs of the body at any given time. This concept is known as "autonomic tone." **Autonomic Tone:** Autonomic tone refers to the ongoing, baseline level of activity and tension maintained by both the sympathetic and parasympathetic divisions of the ANS in a particular organ or tissue. In other words, even at rest, both divisions are active to some extent, exerting their influence to keep the body in a state of readiness and responsiveness to changing conditions. Here's how autonomic tone works: 1. **Balance between Sympathetic and Parasympathetic Activity:** The ANS maintains a balance of activity between the sympathetic and parasympathetic divisions. This balance ensures that physiological processes are regulated appropriately for the body's current needs. 2. **Dynamic Adjustment:** Depending on the specific situation, one division may dominate over the other to adjust organ function. For example: - In a resting state or during periods of low stress, the parasympathetic tone may predominate. This results in a slowed heart rate, relaxed airways, and enhanced digestion and nutrient absorption. - In response to stress or emergencies, the sympathetic tone may increase, leading to increased heart rate, dilation of airways, and the mobilization of energy stores. 3. **Continuous Regulation:** Autonomic tone allows for continuous regulation of organ function. For instance, the heart rate is constantly adjusted by autonomic tone to maintain an appropriate rate for the body's needs, whether at rest or during physical activity. 4. **Adaptive Response:** Autonomic tone ensures that the body can quickly respond to changes in the environment or internal conditions. For example, if you suddenly need to sprint, the sympathetic division can quickly increase heart rate and redirect blood flow to muscles, preparing you for action. In summary, autonomic tone is the baseline level of activity maintained by both the sympathetic and parasympathetic divisions of the ANS, ensuring that the body is always prepared to respond to changing conditions. It is this dynamic balance and coordination between the two divisions that allow for the precise regulation of physiological processes and the ability to adapt to a wide range of situations. Therefore, it cannot be said that one division is completely inactive while the other is active; instead, both divisions are active simultaneously, with their influence varying depending on the body's needs.

It cannot be said that at any given moment, either the sympathetic or the parasympathetic division of the autonomic nervous system (ANS) is exclusively active because the ANS operates with a continuous balance and interplay between the two divisions. This balance is maintained to varying degrees depending on the specific needs of the body at any given time. This concept is known as "autonomic tone." **Autonomic Tone:** Autonomic tone refers to the ongoing, baseline level of activity and tension maintained by both the sympathetic and parasympathetic divisions of the ANS in a particular organ or tissue. In other words, even at rest, both divisions are active to some extent, exerting their influence to keep the body in a state of readiness and responsiveness to changing conditions. Here's how autonomic tone works: 1. **Balance between Sympathetic and Parasympathetic Activity:** The ANS maintains a balance of activity between the sympathetic and parasympathetic divisions. This balance ensures that physiological processes are regulated appropriately for the body's current needs. 2. **Dynamic Adjustment:** Depending on the specific situation, one division may dominate over the other to adjust organ function. For example: - In a resting state or during periods of low stress, the parasympathetic tone may predominate. This results in a slowed heart rate, relaxed airways, and enhanced digestion and nutrient absorption. - In response to stress or emergencies, the sympathetic tone may increase, leading to increased heart rate, dilation of airways, and the mobilization of energy stores. 3. **Continuous Regulation:** Autonomic tone allows for continuous regulation of organ function. For instance, the heart rate is constantly adjusted by autonomic tone to maintain an appropriate rate for the body's needs, whether at rest or during physical activity. 4. **Adaptive Response:** Autonomic tone ensures that the body can quickly respond to changes in the environment or internal conditions. For example, if you suddenly need to sprint, the sympathetic division can quickly increase heart rate and redirect blood flow to muscles, preparing you for action. In summary, autonomic tone is the baseline level of activity maintained by both the sympathetic and parasympathetic divisions of the ANS, ensuring that the body is always prepared to respond to changing conditions. It is this dynamic balance and coordination between the two divisions that allow for the precise regulation of physiological processes and the ability to adapt to a wide range of situations. Therefore, it cannot be said that one division is completely inactive while the other is active; instead, both divisions are active simultaneously, with their influence varying depending on the body's needs.