Activity 3
1. You have been to an ‘eat all you can’ buffet and have consumed large amounts of food. After returning home, you recline on the couch to watch television. Which division of the nervous system will be handling your body’s after-dinner activities? List several organs involved, the major nerve supply to each organ, and the effects of the nervous system on their functions.
The division of the nervous system that will be handling the body’s after-dinner activities is the Parasympathetic division of the Autonomic Nervous System (ANS), which is responsible for the “rest-and-digest” activities of the body.
During digestion, the organs involved are the stomach, pancreas, liver, gallbladder, small intestine, large intestine, and rectum. The major nerve supply to each organ is the vagus nerve (vagal nerves) which are the main nerves of the parasympathetic nervous system responsible for digestion. It transmits signals from the brain to the gut and helps in digestion and regulation of bowel movements.
The parasympathetic stimulation of the nervous system in the stomach and intestines leads to increased motility and relaxation of the sphincters. And this stimulation increases gastric secretions too which aid in digestion. Moreover, the parasympathetic stimulation of the pancreas leads to the release of digestive enzymes and insulin. Ultimately, in the gallbladder, the parasympathetic stimulation stimulates contraction which releases bile that helps break down fats and carry away wastes.
2. Your friend is driving home from work, listening to her favorite music, when suddenly a bicycle came out of nowhere. She manages to swerve avoiding hitting the bicycle. She continued to drive home but she noticed that her heart is beating fast, she had goose bumps, and her hands were sweaty. How would you explain these effects?
As the bicycle suddenly came out of nowhere in front of my friend who is driving, this event has activated the Sympathetic division of her Autonomic Nervous System (ANS) which is responsible for the “fight-or-flight” response of the body whenever we encounter a stressful or emergency situation. The increased heart rate, goose bumps, and sweaty hands are a result of the secretion of adrenaline and norepinephrine from the adrenal medulla which causes these effects to prolong and intensify.