Parasympathetic Division

Definition

The parasympathetic division is a part of the autonomic nervous system responsible for promoting the 'rest and digest' functions in the body. It operates to conserve energy by slowing down heart rate, increasing intestinal and gland activity, and relaxing sphincter muscles. This division is crucial for maintaining homeostasis and balancing the body's responses to stress and relaxation.

5 Must Know Facts For Your Next Test

1. The parasympathetic division is primarily activated during restful states, allowing the body to conserve energy and recover from stress.
2. Its actions are mainly mediated through acetylcholine, a neurotransmitter that promotes calmness and relaxation in target organs.
3. Major functions of the parasympathetic division include stimulating salivation, lacrimation (tear production), urination, digestion, and defecation.
4. The 'rest and digest' response reduces respiratory rate and heart rate while promoting digestion by increasing blood flow to the gastrointestinal tract.
5. Dysfunction in the parasympathetic division can lead to issues like digestive problems or increased stress responses due to a lack of balance with the sympathetic division.

Review Questions

• How does the parasympathetic division contribute to maintaining homeostasis in the body?
  • The parasympathetic division plays a crucial role in maintaining homeostasis by promoting bodily functions that occur during restful states. By slowing heart rate, enhancing digestion, and facilitating relaxation in various systems, it helps restore balance after periods of stress or activity. This regulation ensures that energy conservation processes are optimized while allowing for recovery and repair of tissues.
• Compare and contrast the functions of the sympathetic and parasympathetic divisions of the autonomic nervous system.
  • The sympathetic division prepares the body for 'fight or flight' situations by increasing heart rate, dilating airways, and redirecting blood flow to muscles. In contrast, the parasympathetic division promotes 'rest and digest' activities, slowing down heart rate, stimulating digestive processes, and conserving energy. Together, these two divisions work in opposition to maintain physiological balance according to varying environmental demands.
• Evaluate the impact of prolonged stress on the balance between sympathetic and parasympathetic divisions in an individual's health.
  • Prolonged stress can lead to an overactive sympathetic division, resulting in chronic conditions such as hypertension or anxiety. This imbalance often suppresses the parasympathetic division's ability to promote relaxation and recovery, leading to digestive issues and impaired immune function. The lack of proper regulation may create a cycle where stress exacerbates health problems, highlighting the need for effective stress management strategies to restore harmony between these divisions.

Related terms

Sympathetic Division: The sympathetic division is the other branch of the autonomic nervous system, which prepares the body for 'fight or flight' responses during stressful situations by increasing heart rate and redirecting blood flow to muscles.

Autonomic Nervous System: The autonomic nervous system regulates involuntary bodily functions, including heart rate, digestion, and respiratory rate, and is divided into the sympathetic and parasympathetic divisions.

Vagus Nerve: The vagus nerve is a critical component of the parasympathetic division, responsible for transmitting signals that promote rest and digestive processes, influencing heart rate, gastrointestinal function, and more.