1. The parasympathetic nervous system handles the after-dinner activities of the body. The organs involved here, their corresponding major nerve supply, and the effects of the nervous system on their functions are as follows:
- Salivary Glands
- Major Nerve Supply: Glossopharyngeal nerve (CN IX)
- Effects of the PNS: Stimulates saliva flow
- Lungs
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Tightens the bronchi in the lungs
- Heart
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Lowers the heart rate
- Gallbladder
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Stimulates contraction to bile release
- Stomach
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Increases gastric secretions and stimulates digestion
- Pancreas
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Release of digestive enzymes and insulin
- Intestines
- Major Nerve Supply: Vagus nerve (X)
- Effects of the PNS: Increases motility
- Bladder
- Major Nerve Supply: Pelvic parasympathetic nerve
- Effects of the PNS: Controls bladder contractions and passage of urine
- Rectum
- Major Nerve Supply: Pelvic parasympathetic nerve
- Effects of the PNS: Regulates storage capacity
2. These effects are due to the sympathetic nervous system. The sympathetic nervous system controls the fight or flight response which activates in dangerous or stressful situations. It causes the heart rate to increase, hair to stand up, and produces perspiration.