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 parasympathetic nervous system (PNS) is the division of the nervous system that will be handling the body’s after-dinner activities.
As this division is also known as the rest and digest system, controlling the body during relaxation or after the fight-or-flight response, it increases the rate of digestion and diverts the energy to help in the digestion of food.
Herewith, several organs which are involved in the PNS and digestion process are as follows:
|
Organ |
Major Nerve Supply |
Effect of Nervous System on Function |
|
Salivary glands |
Facial Nerve (CN VII) |
Controls saliva production; stimulates saliva flow |
|
Esophagus |
Vagus Nerve (CN X) |
Allows substances like food and liquids to pass through due to involuntary muscle contractions, as commanded |
|
Lungs |
Vagus Nerve (CN X) |
Controls respiration |
|
Heart |
Vagus Nerve (CN X) |
Regulates heart rate |
|
Pancreas |
Vagus Nerve (CN X) |
Allows for the secretion of endocrine and exocrine gland substances, in line with the internal or external body conditions |
|
Liver |
Vagus Nerve (CN X) |
Detoxifies metabolites and regulates metabolism; produces chemicals as needed in digestion |
|
Stomach |
Vagus Nerve (CN X) |
Helps in gastrointestinal motility |
|
Small and Large intestines |
Vagus Nerve (CN X) |
Regulates intestinal activities, such as the absorption of nutrients, secretion and digestion, and transportation of other substances |
|
Gallbladder |
Vagus Nerve (CN X) |
Controls the release of bile to help food digestion |
|
Urinary bladder |
Vagus Nerve (CN X) |
Controls its contraction and the passage of urine |
|
Rectum |
Pelvic Nerve |
Controls the defecation process |
All in all, the major nerve supply to almost all the organs involved in the PNS, especially in the context of digestion, is the Vagus Nerve (Cranial Nerve X). These organs work hand-in-hand in order to contribute to the digestion of food, and other bodily functions.
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 heads were sweaty. How would you explain these effects?
Due to the sudden emergence of the bicycle out of nowhere, the sympathetic nervous system (SNS) responds to the situation, also known as the fight-or-flight response. Herewith, the SNS is involved in the increase of a person’s movement, strength, and response to stressful situations that may threaten survival. As demonstrated in the situation of her friend, the fight-or-flight response may induce a state of panic, as such, my friend suddenly swerved to avoid the bicycle accident. The increase of heart rate, goosebumps, and perspiration indicates the body’s response to fear and stress—implying the work of the SNS.
References
Tortora, G. J., & Derrickson, B. (2014). Principles of Anatomy and Physiology (14th ed.). Wiley.