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.
Division: Parasympathetic nervous system
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Often referred to as the "rest-and-digest" division
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Its activities conserve and restore body energy during times of rest or digesting a meal
|
Organ |
Major nerves supply |
Effects of the nervous system on their functions |
|
Salivary glands |
Facial nerve (VII) |
The autonomic nervous system controls saliva production, both the volume and type of saliva secreted. |
|
Esophagus |
Vagus nerve (X) |
Controlled by an intrinsic nervous system and by input from the central nervous system through the vagus nerve. It may elicit either contraction or relaxation of the lower esophageal sphincter. Allows the passage of food and liquids. |
|
Heart |
Vagus nerve (X) |
The sympathetic nervous system (SNS) controls the heart-rate acceleration, increased cardiac contractility, reduced venous capacitance, and peripheral vasoconstriction. |
|
Lungs |
Vagus nerve (X) |
The nervous system controls respiration. The parasympathetic system slows our breathing rate, while the sympathetic system increases our breathing rate. |
|
Stomach |
Vagus nerve (X) |
The enteric nervous system controls motility, ion transport associated with secretion and absorption, and gastrointestinal blood flow. |
|
Small and large intestines |
Vagus nerve (X) |
The enteric nervous system regulates the activities of intestines, such as absorption of nutrients, and transportation of other substances. |
|
Liver |
Vagus nerve (X) |
Sympathetic release of adrenalin and substance P (SP) causes contraction of the liver sinusoids, whereas parasympathetic release of acetylcholine and vasoactive intestinal peptide (VIP) causes relaxation. Also regulates metabolism. |
|
Gallbladder |
Vagus nerve (X) |
The nervous system controls the release of bile help with digestion of food. |
|
Urinary bladder |
Vagus nerve (X) |
The nervous system controls the nerves carrying messages to tell the muscles of the bladder to either tighten or release; hence decides the passage of urine. |
|
Rectum |
Pelvic nerve |
The nervous system controls the process of defecation. |
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 goosebumps, and her heads were sweaty. How would you explain these effects?
- The division responsible for these effects is the sympathetic nervous system, often referred to as “fight-or-flight.” In this scenario, she was in a threatening situation because there could have been an accident if she was not able to swerve. Because of the sudden happening, she showed these effects because her sympathetic nervous system detected that there was a threat to homeostasis. Under such conditions, this division brings about many effects that help the individual cope with the stressor. In this case, the sudden bicycle that disturbed her relaxed self. Hence, the sympathetic nervous system did its work.
References:
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Marieb, E. & Keller, S. (2018). Essentials of Human Anatomy & Physiology. New York, NY: Pearson Education
Neurogenic Bladder. (2019, November 19). John Hopkins Medicine. Retrieved from
https://www.hopkinsmedicine.org/health/conditions-and-diseases/neurogenic-bladder
Park, H. & Conklin, J.L. (1999). Neuromuscular control of esophageal peristalsis. Curr Gastroenterol Rep., 1(3), 186-97. doi: 10.1007/s11894-999-0033-3.
Rea, P. (2014). Chapter 10 - Vagus Nerve. Clinical Anatomy of the Cranial Nerves, 105-116. https://doi.org/10.1016/B978-0-12-800898-0.00010-5
The Enteric Nervous System. (n.d.). Retrieved from
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/gi_nervous.html
The Profile of Saliva. (2015, February 10). Retrieved from https://www.scopeaust.org.au/information-resources-hub/resources-download/profile-saliva/#:~:text=The%20type%20of%20nerve%20system,nerves%3B%20sympathetic%20and%20parasympathetic%20nerves.
Tortora, G. & Derrickson, B. (2014). Principles of Anatomy and Physiology (14th ed.). New Jersey, NJ: Wiley
Zhang, D. & Anderson, A. (2014). The Sympathetic Nervous System and Heart Failure. Cardiol Clin., 32(1), 33-vii. doi: 10.1016/j.ccl.2013.09.010