What are the general functions of sympathetic nervous system and parasympathetic system?

The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS) are two branches of the autonomic nervous system (ANS), which is responsible for regulating involuntary bodily functions such as heart rate, digestion, and respiration. The SNS and PNS work in opposition to each other to maintain homeostasis in the body. Here are their general functions:

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.