What are the general functions of sympathetic nervous system and parasympathetic system?
1. Sympathetic Nervous System (SNS):
- The SNS is often referred to as the "fight or flight" system.
- It prepares the body for physical activity and responses to stressful situations.
- Activates the release of epinephrine (adrenaline) from the adrenal glands.
- Increases heart rate, dilates the pupils, and stimulates sweating.
- Inhibits digestion and salivation to redirect energy to muscles.
- Regulates blood pressure and respiration.
- Plays a role in sexual arousal and ejaculation in males.
2. Parasympathetic Nervous System (PNS):
- The PNS is often called the "rest and digest" system.
- It conserves energy and promotes bodily functions that occur at rest.
- Activates the release of acetylcholine from nerve endings.
- Decreases heart rate and dilates blood vessels.
- Stimulates digestion and salivation.
- Facilitates urination and defecation.
- Regulates pupillary constriction.
- Slows down breathing rate.
The SNS and PNS work in coordination to maintain a dynamic equilibrium in the body, ensuring that physiological functions are appropriately adjusted in response to internal and external stimuli. For example, when facing a stressful situation, the SNS activates, increasing heart rate and preparing the body for action, while the PNS becomes less active, reducing non-essential bodily functions. Conversely, during periods of rest and relaxation, the PNS is dominant, allowing the body to conserve energy and focus on restorative processes.