Anatomy & Physiology: The Unity of Form and Function, 7th Edition

Published by McGraw-Hill Education
ISBN 10: 0073403717
ISBN 13: 978-0-07340-371-7

Chapter 17 - Section 17.5 - Study Guide - Assess Your Learning Outcomes - Page 669: 3

Answer

The stress response, also known as the general adaptation syndrome (GAS), was initially described by Hans Selye and consists of three stages: the alarm stage, the resistance stage, and the exhaustion stage. Each stage is characterized by specific physiological responses and hormonal changes. 1. **Alarm Stage**: - **Dominant Hormone**: The dominant hormone during the alarm stage is adrenaline (epinephrine), released by the adrenal glands in response to a perceived threat or stressor. - **Physiological Effects**: Adrenaline triggers the "fight or flight" response, which prepares the body for immediate action. This includes increased heart rate, rapid breathing, dilated pupils, increased blood flow to muscles, and enhanced alertness. The body's resources are mobilized to respond to the stressor. 2. **Resistance Stage**: - **Dominant Hormones**: During the resistance stage, the body's response shifts from the initial burst of adrenaline to the release of stress hormones such as cortisol and other glucocorticoids. - **Physiological Effects**: Cortisol helps regulate metabolism and maintain energy supplies during prolonged stress. It also suppresses functions that are not immediately necessary for dealing with the stressor, such as digestion and immune responses. The body adapts to the ongoing stressor, and if the stress continues, it may lead to certain physiological changes such as increased blood pressure and changes in immune system function. 3. **Exhaustion Stage**: - **Dominant Hormones**: The exhaustion stage is characterized by an increased release of cortisol and other stress hormones, but the body's resources become depleted. - **Physiological Effects**: Prolonged and chronic stress can lead to the exhaustion of the body's energy reserves, resulting in physical and mental health problems. The immune system may become compromised, making the individual more susceptible to illnesses. Additionally, chronic stress can contribute to conditions like cardiovascular disease, anxiety, and depression. **Transition Between Stages**: The transition between stages is marked by the body's response to the stressor and the duration of the stress exposure: - **Alarm to Resistance**: The transition from the alarm stage to the resistance stage occurs when the initial adrenaline rush subsides, and the body begins to regulate its stress response using cortisol and other stress hormones. This shift helps the body sustain its energy and cope with the ongoing stressor. - **Resistance to Exhaustion**: The transition from the resistance stage to the exhaustion stage occurs when the body's resources become significantly depleted due to prolonged exposure to stress. If the stressor persists and the body is unable to adequately recover, it can lead to a state of exhaustion, where physical and mental health decline. It's important to note that the stress response can vary from person to person, and the progression through these stages may be influenced by factors such as genetics, individual coping mechanisms, and the nature of the stressors themselves. Chronic and excessive stress can have detrimental effects on overall health and well-being, so it's crucial to manage stress effectively through relaxation techniques, healthy lifestyle choices, and seeking support when needed.

Work Step by Step

The stress response, also known as the general adaptation syndrome (GAS), was initially described by Hans Selye and consists of three stages: the alarm stage, the resistance stage, and the exhaustion stage. Each stage is characterized by specific physiological responses and hormonal changes. 1. **Alarm Stage**: - **Dominant Hormone**: The dominant hormone during the alarm stage is adrenaline (epinephrine), released by the adrenal glands in response to a perceived threat or stressor. - **Physiological Effects**: Adrenaline triggers the "fight or flight" response, which prepares the body for immediate action. This includes increased heart rate, rapid breathing, dilated pupils, increased blood flow to muscles, and enhanced alertness. The body's resources are mobilized to respond to the stressor. 2. **Resistance Stage**: - **Dominant Hormones**: During the resistance stage, the body's response shifts from the initial burst of adrenaline to the release of stress hormones such as cortisol and other glucocorticoids. - **Physiological Effects**: Cortisol helps regulate metabolism and maintain energy supplies during prolonged stress. It also suppresses functions that are not immediately necessary for dealing with the stressor, such as digestion and immune responses. The body adapts to the ongoing stressor, and if the stress continues, it may lead to certain physiological changes such as increased blood pressure and changes in immune system function. 3. **Exhaustion Stage**: - **Dominant Hormones**: The exhaustion stage is characterized by an increased release of cortisol and other stress hormones, but the body's resources become depleted. - **Physiological Effects**: Prolonged and chronic stress can lead to the exhaustion of the body's energy reserves, resulting in physical and mental health problems. The immune system may become compromised, making the individual more susceptible to illnesses. Additionally, chronic stress can contribute to conditions like cardiovascular disease, anxiety, and depression. **Transition Between Stages**: The transition between stages is marked by the body's response to the stressor and the duration of the stress exposure: - **Alarm to Resistance**: The transition from the alarm stage to the resistance stage occurs when the initial adrenaline rush subsides, and the body begins to regulate its stress response using cortisol and other stress hormones. This shift helps the body sustain its energy and cope with the ongoing stressor. - **Resistance to Exhaustion**: The transition from the resistance stage to the exhaustion stage occurs when the body's resources become significantly depleted due to prolonged exposure to stress. If the stressor persists and the body is unable to adequately recover, it can lead to a state of exhaustion, where physical and mental health decline. It's important to note that the stress response can vary from person to person, and the progression through these stages may be influenced by factors such as genetics, individual coping mechanisms, and the nature of the stressors themselves. Chronic and excessive stress can have detrimental effects on overall health and well-being, so it's crucial to manage stress effectively through relaxation techniques, healthy lifestyle choices, and seeking support when needed.
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