Sympathetic Nervous System

Definition

The sympathetic nervous system is a division of the autonomic nervous system that is responsible for the body's fight-or-flight response. It prepares the body to react to perceived threats or stressful situations by increasing heart rate, blood pressure, and respiration, while also redirecting blood flow away from the digestive system and towards the muscles.

5 Must Know Facts For Your Next Test

1. The sympathetic nervous system originates in the thoracic and lumbar regions of the spinal cord and extends to various organs and glands throughout the body.
2. Activation of the sympathetic nervous system leads to the release of the neurotransmitters norepinephrine and epinephrine, which trigger the body's stress response.
3. The sympathetic nervous system increases heart rate, blood pressure, and breathing rate, dilates the pupils, and redirects blood flow away from the digestive system and towards the muscles.
4. The sympathetic nervous system also stimulates the release of glucose and fats from storage to provide energy for the body's fight-or-flight response.
5. Chronic activation of the sympathetic nervous system can lead to various health issues, such as high blood pressure, heart disease, and anxiety.

Review Questions

• Describe the main functions of the sympathetic nervous system and how it prepares the body for a stress response.
  • The sympathetic nervous system is responsible for the body's fight-or-flight response. When activated, it increases heart rate, blood pressure, and breathing rate to provide more oxygen and energy to the muscles. It also dilates the pupils, redirects blood flow away from the digestive system, and stimulates the release of glucose and fats to fuel the body's reaction to a perceived threat or stressful situation. This physiological response prepares the individual to either confront the challenge or flee from it.
• Explain the relationship between the sympathetic and parasympathetic nervous systems and how they work together to maintain homeostasis.
  • The sympathetic and parasympathetic nervous systems work in opposition to maintain homeostasis within the body. The sympathetic nervous system is responsible for the body's stress response, while the parasympathetic nervous system is responsible for the body's rest-and-digest response. When the sympathetic nervous system is activated, it prepares the body for action by increasing heart rate, blood pressure, and respiration. Conversely, the parasympathetic nervous system slows down these bodily functions, conserving energy and promoting normal digestion and other restorative processes. The two systems work together to keep the body in a state of balance, with the sympathetic system responding to perceived threats and the parasympathetic system restoring the body to a state of calm and relaxation.
• Analyze the potential long-term effects of chronic activation of the sympathetic nervous system and discuss strategies for managing stress and maintaining a healthy balance between the two divisions of the autonomic nervous system.
  • Chronic activation of the sympathetic nervous system, often due to prolonged stress, can have serious negative consequences for an individual's health. Sustained high levels of stress hormones like norepinephrine and epinephrine can lead to issues such as high blood pressure, heart disease, anxiety, and even depression. To maintain a healthy balance between the sympathetic and parasympathetic nervous systems, it is important to engage in stress-management techniques like regular exercise, meditation, and mindfulness practices. Getting enough sleep, eating a balanced diet, and seeking social support can also help the body's autonomic nervous system function optimally and avoid the detrimental effects of chronic sympathetic activation. By adopting a holistic approach to managing stress and promoting relaxation, individuals can better maintain homeostasis and support overall well-being.

Related terms

Autonomic Nervous System: The autonomic nervous system controls involuntary bodily functions, such as heart rate, breathing, and digestion, and is divided into the sympathetic and parasympathetic nervous systems.

Parasympathetic Nervous System: The parasympathetic nervous system is responsible for the body's rest-and-digest response, which conserves energy and promotes normal bodily functions.

Fight-or-Flight Response: The physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival, which prepares the body to either fight or flee.