Enteric nervous system: Read Wikipedia Enteric
nervous system, etc.
https://en.wikipedia.org/wiki/Enteric_nervous_system
https://en.wikipedia.org/wiki/Basal_electrical_rhythm
https://en.wikipedia.org/wiki/Neurogastroenterology.
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The Systems Biology of COVID-19 and the SARS-CoV-2 virus. The class will build a foundation that includes the emergence of complexity, simple biological subsystems, their reductionist and equivalent toy and organ-chip models, and the measurements required to specify model architecture and parameters. Applications to biology, physiology, medicine, chemical and biological defense, pharmacology, drug discovery, and toxicology. UGrad: PHYS 240 01 and BME 290B; Grad: PHYS 326 and BME 395C.
0) KNEW
ReplyDeleteI knew that the enteric nervous system could function independently, but is also innervated by the ANS. I knew that the interstitial cells of Cajal are the pacemakers of the gut.
1) LEARNED
The enteric nervous system derives from neural crest cells. I learned that the Auerbach's plexus is similar to the CNS in that it has sensory receptors, mechanoreceptors, and chemoreceptors. It is the parasympathetic nucleus of origin for the vagus nerve and communicates with the medulla oblangata. There are many things that can affect gastric mobility, including GLP-1, which is a Ileal Brake, meaning it inhibits upper GI tract motility when there are a lot of nutrients further down in the gut.
2) QUESTIONS
How do problems in the Auerbach's plexus cause upstream effects? How are they manifested? What kind of theoretical work has been conducted on the evolution of the enteric nervous system? What are the main theories for why we have a "second brain"?
3) PRESENTATION
Interstitial cells of Cajal
4) THOUGHTS
I enjoyed reading these articles. I already knew a bit about the pacemaking/peristalsis, but it was interesting to see more about the anatomy (including Auerbach's plexus and Meissner's plexus).
0) What I Already Knew: The enteric nervous system is part of the autonomic nervous system. It relates to the GI tract.
ReplyDelete1) Most Important Thing I Learned: The enteric system can operate without the presence of the other components of the autonomic nervous system. It can operate autonomously. A diffusion barrier similar to the blood-brain barrier exists around the ganglia.
2) Questions: Does the microbiota play a role in functional GI disorders?
3) Potential Class Presentation: The two forms of plexus mentioned in the wikipedia page on neurogastroenterology
4) Thoughts: Knew little besides what we have discussed so far in class. Good to get a simple introduction.
0) What I already knew:
ReplyDeleteI already knew some of the basic components of the enteric nervous system. For example, I learned briefly in other classes about how the enteric nervous system is embedded in the GI system, and has two generic classes of ganglia: the myenteric and the submucosal plexuses.
1) Most important thing I learned:
One thing I learned that is really fascinating is that the enteric nervous system acts like a "second brain," in that it operates autonomously, and communicates to the central nervous system through the vagus nerve for the parasympathetic system and the prevertebral ganglia for the sympathetic nervous system. In addition, the enteric nervous system has its OWN blood-brain barrier, which surrounds ganglia capillaries just like the blood-brain barrier of cerebral blood vessels. These properties will be key to incorporate into our gut-brain axis on a chip.
2) Questions:
How do enteric glial cells interact with gut microbiota?
3) Presentation Topic:
Neural Crest Cell Differentiation and the Enteric Nervous System
4) Thoughts:
I think this wikipedia article will be crucial to our class gut-brain axis on a chip. The developmental origin of the enteric nervous system, the blood-brain barrier of the enteric system, as well as the different types of ganglia in the submucosal and muscularis propria are all key components of the neural/electric regulation of the gut-brain axis.
0: The enteric nervous system is in the gut.
ReplyDelete1: The ENS is a system of neurons connected to the gut and is formed from the neural crest. The ENS has a dense array of neurons. There are two type of ganglia: myenteric plexuses and submucosal plexuses. Myenteric plexuses are in the muscularis externa, while submucosal plexuses are in the submucosa. The ENS can communicate to the brain via the SNS and the PNS.
2: How long has the ENS been studied? What is currently being investigated with the ENS?
Is the ENS present in other organisms? Is it only in vertebrates?
3: ENS Development
4: Understanding the ENS will be critical for understanding the GBA
0) Knew: enteric nervous system runs the length of the digestive tract and controls peristalsis as a division of the autonomic nervous system.
ReplyDelete1) Learned: Auerbach's plexus supplies motor inputs to muscularis externa, both sympathetic and parasympathetic. Meissner's plexus is strictly parasympathetic and runs from Auerbach's plexus into the mucosa layer of gastrointestinal wall.
2) Question: Auerbach's plexus operates in two directions; it's both sensory and excitatory. Is Meissner's plexus strictly sensory, or does it stimulate movement of epithelium with inputs from Auerbach's plexus?
3) Presentation: Map of innervation in the gut-brain-axis, with divisions, functions, and names.
4) Thoughts: This is a good high-level breakdown of the enteric nervous system, which is beyond vital to the idea of the gut-brain-axis. It would be useful to know the degree to which the enteric nervous system is simply a control for gut movement, and how it may affect information flow in the opposite direction (gut to brain/CNS).
0: I already knew that the ENS is part of the autonomic nervous system, but that it can function almost entirely independently.
ReplyDelete1: I learned that the ENS has a diffusion barrier that's similar to the blood-brain barrier, which is really interesting because I had assumed that the BBB was unique. I'm not sure how well this could be modeled by an organ on a chip.
2. What mechanical/electrical substitute could be used to simulate the basal electrical rhythm/peristalsis in a gut on a chip model?
3. Presentation topic: maybe dive further into the relationship between gut/brain serotonin and dopamine?
4. Thoughts: It was definitely helpful to get a good basic understanding of gut/brain electrophysiology- I feel like we'll be able to have really interesting discussions once we're all on the same page with the physiological system we're looking at.
0. From previous discussions in the class, I knew that the enteric nervous system enervates the GI tract.
ReplyDelete1. This is not a component of the nervous system that I think about often, so most of this information was new to me.
2. How are the different types of neurons in the ENS distributed? Are they all mixed together or are certain types localized to specific parts of the GI tract? How does the ENS interact with other parts of the gut-brain axis like the microbiome?
3. I think a more in depth presentation about the ENS might be helpful. This was a nice overview, but I think we’ll need some more information about the organization of this nervous system and how it interacts with other parts of the GI tract and brain for our class project.
4. I’m a little bit nervous about the fact that the ENS uses more than 30 neurotransmitters. Are these all produced by the neurons in the ENS? Which neurotransmitters are critical to ENS functioning or do we need all of the neurotransmitters?
0) What I already knew
ReplyDeleteThe enteric system of the “brain” of the gut!
I learned about action potentials in my physiology class this semester. The sympathetic nervous system (fight or flight) inhibits gastric motility, and parasympathetic nervous system (rest and digest) stimulates gastric motility.
Peristalsis is the contraction and relaxation of muscles in the GI tract.
1) What I learned
The enteric nervous system is involved in the coordination of reflexes. It can operate independently of the brain and spinal cord.
Contraction of smooth muscle in the GI tract depends on calcium release. The frequency of contraction is different at different locations of the GI tract. This reminds of different frequencies of sound in different parts of the cochlea in the ear.
Peristalsis occurs in one direction, but segmented contractions occur simultaneously in both directions.
2) Most pressing questions
In the reflex arc for the autonomic nervous system, the integrating center is the brain or the spinal cord depending if it was a learned or intrinsic reflex. In the reflex arc of the enteric nervous system, how can the enteric nervous system itself act as the integrating center?
3) Suggestion for class presentation:
How does the enteric nervous system operate without the spinal cord or brain? Physiologically how is this possible?
4) Thoughts
It is strange to me that the enteric nervous system uses itself as the integrating center…I am going to look more in to how this is possible! My physiology class skipped the enteric nervous system. I am going to do some more independent reading of the enteric nervous system.
0) What I already knew
ReplyDeleteEnteric nervous system is autonomous, not under voluntary control.
1) The most important think I learned
It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems. However, vertebrate studies show that when the vagus nerve is severed, the enteric nervous system continues to function.
BER is crucial in order for contraction to occur in that it stimulates action potential.
2) My most pressing question from the reading
Is it possible for enteric nervous system to control gut activity without the input from the brain?
How does calcium oscillation influence the contraction of smooth muscles?
3) A suggestion for a class discussion
Enteric nervous system versus vagus nerve
4) Any thoughts that you might have on the class or paper
I think learning about the interplay between the brain and ENS is very important for our modeling. Also it may be helpful to know about the BER in case we need to model muscular activities.