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The Second Brain: A Groundbreaking New Understanding of Nervous Disorders of the Stomach and Intestine
“Persuasive, impassioned... hopeful news [for those] suffering from functional bowel disease.” — New York Times Book Review Dr. Gershon’s groundbreaking book fills the gap between what you need to know—and what your doctor has time to tell you. Dr. Michael Gershon has devoted his career to understanding the human bowel (the stomach, esophagus, small intestine, and colon). His thirty years of research have led to an extraordinary rediscovery: nerve cells in the gut that act as a brain. This "second brain" can control our gut all by itself. Our two brains—the one in our head and the one in our bowel—must cooperate. If they do not, then there is chaos in the gut and misery in the head—everything from "butterflies" to cramps, from diarrhea to constipation. Dr. Gershon's work has led to radical new understandings about a wide range of gastrointestinal problems including gastroenteritis, nervous stomach, and irritable bowel syndrome. The Second Brain represents a quantum leap in medical knowledge and is already benefiting patients whose symptoms were previously dismissed as neurotic or "it's all in your head."
336 pages, Paperback
First published October 4, 1998
248 people are currently reading
2472 people want to read
About the author
Michael D. Gershon
6 books12 followersChairman of the department of anatomy and cell biology at Columbia University.
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Displaying 1 - 30 of 67 reviews
December 22, 2015
If you are planning to be a student of medicine or neuro-psychology, then you seriously might start with this book. Gershon shares his 30 years of research of the gut and its enteric nervous system in a detailed story account, which is technical but very readable to the interested student. It may not be on your official prerequisite reading list given to you by the college you are about to attend, but trust me and read it anyway because it deserves to be read for its revolutionary content. Until his research in this book revealed that the gut has nerve cells that act as a second brain, the gut went far too long unrecognized as capable of being an independent functioning organism, and its importance in both medical health as well as psychological health had taken a back seat to the head brain.
I have used his remarkable work as a primary reference in my own book to further validate psychological findings in my own clinical studies on the intelligence of the gut instincts and a new gut psychology. Without his work, my thesis would have lacked the neurologicaI and biological validation it needed to come forth as a viable new theory in modern psychological thought. I highly recommend Dr. Michael Gershon's groundbreaking book.
Martha Char Love,
author of What's Behind Your Belly Button? A Psychological Perspective of the Intelligence of Human Nature and Gut Instinct and
Increasing Intuitional Intelligence: How the Awareness of Instinctual Gut Feelings Fosters Human Learning, Intuition, and Longevity
I have used his remarkable work as a primary reference in my own book to further validate psychological findings in my own clinical studies on the intelligence of the gut instincts and a new gut psychology. Without his work, my thesis would have lacked the neurologicaI and biological validation it needed to come forth as a viable new theory in modern psychological thought. I highly recommend Dr. Michael Gershon's groundbreaking book.
Martha Char Love,
author of What's Behind Your Belly Button? A Psychological Perspective of the Intelligence of Human Nature and Gut Instinct and
Increasing Intuitional Intelligence: How the Awareness of Instinctual Gut Feelings Fosters Human Learning, Intuition, and Longevity
April 23, 2013
The Author
The author is not a gastroenterologist, but a neurobiologist, whose interest in the serotonin neurotransmitter took him down into the bowels of medicine. This book is a history of the development of the understanding of the intestinal nervous system, a history in which the author played a major role.
How Science is Actually Done
The author describes numerous experiments he and other conducted to figure out the intestinal nervous system. There is a great deal of information and the writing gets rather technical at times. This would be a good book for a college undergraduate science major to read.
Autonomic Nervous System
The autonomic nervous system is motor not sensory and controls smooth muscles and glands, not skeletal muscles. It has three parts:
• Sympathetic Nervous System
• Parasympathetic Nervous System
• Enteric Nervous System
Sympathetic Nervous System
• The nerve cell bodies are located near the spine
• Its nerves exit the spinal chord near the thoracic and lumbar vertebra
• Controls eye pupil dilation
• Controls male ejaculation
• Its axons release norepinephrine at their synapses
Parasympathetic Nervous System
• Its nerve cell bodies are located near the innervated organ
• Nerves exit the spinal chord near the cranial and sacral vertebra
• The vagus nerve is part of it
• Its axons release acetylcholine at their synapses
Enteric Nervous System
The intestines contain large numbers of interneurons, that is, neurons that connect via synapses only to other neurons, and not to sensory, muscle or gland cells. One of the main neurotransmitters used by these enteric interneurons is serotonin. Serotonin stimulates the peristalsis of the smooth muscles of intestines.
Colon
The colon is also known as the large intestine. It probably evolved to help land animals conserve water. The body moves water from inside the lumen of the colon into the bloodstream by removing salt from the lumen of the colon, which causes the water to follow by osmosis. There are lots of benign, symbiotic bacteria in the colon, but there are few bacteria in the small intestines. The purpose of diarrhea is to cleanse colon of pathogenic bacterial.
Development of the Enteric Nervous System
During embryonic development, the neural crest is formed from cells that migrate from the nearby neural tube. These neural crest cells later migrate to the intestines, where they become the enteric nervous system.
Defects of Intestinal Innervation
• Chagas disease (American trypanosomiasis), a tropical parasitic infection common in Latin America, kills enteric ganglia of Auerbach's myenteric plexus
• Hirschsprung’s Disease (congenital megacolon): babies lack enteric ganglia in the colon, due to a failure in the embryonic development of the enteric nervous system
• Neuronal Intestinal Dysplasia (NID): a congenital disease causing a lack of sympathetic or parasympathetic innervation of the intestines
• From Wikipedia I found that all newborns are kept in the hospital until they have their first bowel movement, in order to identify babies that have intestinal problems, and that in the United Kingdom there is a charity for NID called the Adele Chapman Foundation
Gastric Intrinsic Factor
Gastric glands in the stomach secrete a glycoprotein called gastric intrinsic factor that helps the small intestine absorb vitamin B12.
Liver and Gall Bladder
The liver secretes bile into the duodenum to emulsify fat, which is then digested by the lipase enzyme secreted into the duodenum by the pancreas. Excess bile is stored in the gall bladder. Gall bladder ganglia are part of the enteric nervous system.
Pancreas and the Vagus Nerve
The vagus nerve of the parasympathetic system stimulates the pancreas to increase secretions when eating a meal.
Pancreas and Bicarbonate
• Brunner’s glands of the pancreas produce a bicarbonate alkaline fluid to neutralize the stomach acid in the food that enters the duodenum from the stomach.
• Hormonal regulation: The secretin hormone produced by the duodenal endocrine cells tells the pancreas now much bicarbonate to produce.
• Nerve regulation: The pancreas receives serotonin-releasing neurons from the duodenum which inhibit the release of the bicarbonate.
Pancreas and Digestive Enzymes
• Cholecystokinin is released by endocrine cells in the stomach and travels through the bloodstream to the pancreas, where it stimulates the release of digestive enzymes.
• Gastrin is released by endocrine cells in the duodenum and travels through the bloodstream to the pancreas, where it also stimulates the release of digestive enzymes.
Enterochromaffin Cells
Enterochromaffin cells are found in intestinal lining and were named for the fact that they stain well with chromium dyes, because they have an affinity for chromium. Enterochromaffin cells contain 95% of the body’s serotonin. As was first proposed by the late Edith Bülbring of Oxford University, Fellow of the Royal Society, and pioneer in the study of the physiology of smooth muscle, enterochromaffin cells are sensory receptors that respond to pressure in the intestines by releasing serotonin into the connective tissue of the intestines. The serotonin in the connective tissue then stimulates:
• Secretomotor neurons that in turn stimulate the crypt cells to secrete salt into the lumen, and water then follows the salt into the lumen, due to osmotic pressure
• Enteric nervous system interneurons causing peristalsis
• Neurons that connect to the CNS and cause nausea and vomiting
Serotonin Transporter Protein
Serotonin transporter protein is in the outer membrane of neighbors of the enterochromaffin cells. It removes the serotonin after it has spent enough time stimulating the serotonin receptors.
Interstitial Cells of Cajal
• They are named after are named after the Spaniard Santiago Ramón y Cajal
• They are pacemakers in the enteric nervous system
• They amplify nerve signals
• They originate not in the neural crest, but from mesenchymal precursor cells, from which smooth muscle cells also develop
• Because they are not neurons, the body can produce more of them in adulthood, if some of them become damaged
The author is not a gastroenterologist, but a neurobiologist, whose interest in the serotonin neurotransmitter took him down into the bowels of medicine. This book is a history of the development of the understanding of the intestinal nervous system, a history in which the author played a major role.
How Science is Actually Done
The author describes numerous experiments he and other conducted to figure out the intestinal nervous system. There is a great deal of information and the writing gets rather technical at times. This would be a good book for a college undergraduate science major to read.
Autonomic Nervous System
The autonomic nervous system is motor not sensory and controls smooth muscles and glands, not skeletal muscles. It has three parts:
• Sympathetic Nervous System
• Parasympathetic Nervous System
• Enteric Nervous System
Sympathetic Nervous System
• The nerve cell bodies are located near the spine
• Its nerves exit the spinal chord near the thoracic and lumbar vertebra
• Controls eye pupil dilation
• Controls male ejaculation
• Its axons release norepinephrine at their synapses
Parasympathetic Nervous System
• Its nerve cell bodies are located near the innervated organ
• Nerves exit the spinal chord near the cranial and sacral vertebra
• The vagus nerve is part of it
• Its axons release acetylcholine at their synapses
Enteric Nervous System
The intestines contain large numbers of interneurons, that is, neurons that connect via synapses only to other neurons, and not to sensory, muscle or gland cells. One of the main neurotransmitters used by these enteric interneurons is serotonin. Serotonin stimulates the peristalsis of the smooth muscles of intestines.
Colon
The colon is also known as the large intestine. It probably evolved to help land animals conserve water. The body moves water from inside the lumen of the colon into the bloodstream by removing salt from the lumen of the colon, which causes the water to follow by osmosis. There are lots of benign, symbiotic bacteria in the colon, but there are few bacteria in the small intestines. The purpose of diarrhea is to cleanse colon of pathogenic bacterial.
Development of the Enteric Nervous System
During embryonic development, the neural crest is formed from cells that migrate from the nearby neural tube. These neural crest cells later migrate to the intestines, where they become the enteric nervous system.
Defects of Intestinal Innervation
• Chagas disease (American trypanosomiasis), a tropical parasitic infection common in Latin America, kills enteric ganglia of Auerbach's myenteric plexus
• Hirschsprung’s Disease (congenital megacolon): babies lack enteric ganglia in the colon, due to a failure in the embryonic development of the enteric nervous system
• Neuronal Intestinal Dysplasia (NID): a congenital disease causing a lack of sympathetic or parasympathetic innervation of the intestines
• From Wikipedia I found that all newborns are kept in the hospital until they have their first bowel movement, in order to identify babies that have intestinal problems, and that in the United Kingdom there is a charity for NID called the Adele Chapman Foundation
Gastric Intrinsic Factor
Gastric glands in the stomach secrete a glycoprotein called gastric intrinsic factor that helps the small intestine absorb vitamin B12.
Liver and Gall Bladder
The liver secretes bile into the duodenum to emulsify fat, which is then digested by the lipase enzyme secreted into the duodenum by the pancreas. Excess bile is stored in the gall bladder. Gall bladder ganglia are part of the enteric nervous system.
Pancreas and the Vagus Nerve
The vagus nerve of the parasympathetic system stimulates the pancreas to increase secretions when eating a meal.
Pancreas and Bicarbonate
• Brunner’s glands of the pancreas produce a bicarbonate alkaline fluid to neutralize the stomach acid in the food that enters the duodenum from the stomach.
• Hormonal regulation: The secretin hormone produced by the duodenal endocrine cells tells the pancreas now much bicarbonate to produce.
• Nerve regulation: The pancreas receives serotonin-releasing neurons from the duodenum which inhibit the release of the bicarbonate.
Pancreas and Digestive Enzymes
• Cholecystokinin is released by endocrine cells in the stomach and travels through the bloodstream to the pancreas, where it stimulates the release of digestive enzymes.
• Gastrin is released by endocrine cells in the duodenum and travels through the bloodstream to the pancreas, where it also stimulates the release of digestive enzymes.
Enterochromaffin Cells
Enterochromaffin cells are found in intestinal lining and were named for the fact that they stain well with chromium dyes, because they have an affinity for chromium. Enterochromaffin cells contain 95% of the body’s serotonin. As was first proposed by the late Edith Bülbring of Oxford University, Fellow of the Royal Society, and pioneer in the study of the physiology of smooth muscle, enterochromaffin cells are sensory receptors that respond to pressure in the intestines by releasing serotonin into the connective tissue of the intestines. The serotonin in the connective tissue then stimulates:
• Secretomotor neurons that in turn stimulate the crypt cells to secrete salt into the lumen, and water then follows the salt into the lumen, due to osmotic pressure
• Enteric nervous system interneurons causing peristalsis
• Neurons that connect to the CNS and cause nausea and vomiting
Serotonin Transporter Protein
Serotonin transporter protein is in the outer membrane of neighbors of the enterochromaffin cells. It removes the serotonin after it has spent enough time stimulating the serotonin receptors.
Interstitial Cells of Cajal
• They are named after are named after the Spaniard Santiago Ramón y Cajal
• They are pacemakers in the enteric nervous system
• They amplify nerve signals
• They originate not in the neural crest, but from mesenchymal precursor cells, from which smooth muscle cells also develop
• Because they are not neurons, the body can produce more of them in adulthood, if some of them become damaged
September 17, 2012
“Gut instinct”, “My gut tells me”, “I have butterflies in my stomach” – all the ways that we express emotions and thoughts. Our “guts” (the stomach, esophagus, small intestines, colon) are what Dr. Gershon (a neurobiologist) calls “our second brains” and chaos in one brain creates misery in the other. Consider this: 95% of the body’s serotonin is made in the bowel (serotonin being a key neurotransmitter in the regulation of mood, appetite, and sleep). Dr. Gershon also proposes that “the ugly gut is more intellectual than the heart and may have a greater capacity for feeling”.
This is a very interesting read, and well worth it if you wonder why your gut reacts the way it does. My only (mild) criticism is that the book gets very technical from time to time - as if the reader has switched from being a layperson to a fellow scientist.
This is a very interesting read, and well worth it if you wonder why your gut reacts the way it does. My only (mild) criticism is that the book gets very technical from time to time - as if the reader has switched from being a layperson to a fellow scientist.
December 12, 2013
I picked up this book on the advice of my GI doctor, who basically "prescribed" it for me. I expected a book that would help a little bit in understanding why I'm dealing with GI issues and offer some suggestions on treating it. In fact, the cover of the paperback quotes the _NY Times Book Review_ as saying the book contains "Persuasive, impassioned...hopeful news [for those] suffering from functional bowel disease." What I actually read was something far different than I expected.
The book is basically an overview of research on the enteric nervous system of the gut, including Dr. Gershon's work, which is undoubtedly groundbreaking. While it succeeds as a research review, it does not succeed in the cover's other assertion (from the publisher!) that the book "is already benefitting patients." Uh, nothing I read here is benefitting me. I learned a lot of stuff about biomedical research, but zero on how to help myself. It isn't till the last five pages of this very dense book till the author admits the book will not help such patients, but instead reflects the desire that the research will one day lead to treatment. Given that it took me over two months of part-time reading to get to that conclusion, desperately hoping along the entire way that my reading wasn't for naught, I'm feeling a bit ripped off.
To summarize, then, my issue isn't with the author but really with the publisher, who has totally misrepresented the aim of this book. And I think the _NY Times_ book reviewer only read the last part of this one, too. Very disappointed.
The book is basically an overview of research on the enteric nervous system of the gut, including Dr. Gershon's work, which is undoubtedly groundbreaking. While it succeeds as a research review, it does not succeed in the cover's other assertion (from the publisher!) that the book "is already benefitting patients." Uh, nothing I read here is benefitting me. I learned a lot of stuff about biomedical research, but zero on how to help myself. It isn't till the last five pages of this very dense book till the author admits the book will not help such patients, but instead reflects the desire that the research will one day lead to treatment. Given that it took me over two months of part-time reading to get to that conclusion, desperately hoping along the entire way that my reading wasn't for naught, I'm feeling a bit ripped off.
To summarize, then, my issue isn't with the author but really with the publisher, who has totally misrepresented the aim of this book. And I think the _NY Times_ book reviewer only read the last part of this one, too. Very disappointed.
March 14, 2013
Two months ago I didn't even know that there is such a thing an an enteric nervous system (ENS). Thanks to the Anatomy and Physiology class that I am taking, I learned that it exists. When Martha Char Love reviewed this book, I acquired a desire to learn more about the ENS.
This books starts out like a travelog written by a very engaging writer, who spices his writing with witty humor that is delightful to read. Even though it reads like a travelog, yet the writing is so engaging that I read on, delighted with his surprising comparisons.
However as the book goes on, it gets into detail that me, a person who is not a neurologist, finds to be excessive blow-by-blow details about chemical minutia. It almost seems as if the book was written to document for some future civilization, the long forgotten research done in this generation on enteric neurology.
The last two chapters get back to readable English and summarize why he and other scientists do the work that they do.
This books starts out like a travelog written by a very engaging writer, who spices his writing with witty humor that is delightful to read. Even though it reads like a travelog, yet the writing is so engaging that I read on, delighted with his surprising comparisons.
However as the book goes on, it gets into detail that me, a person who is not a neurologist, finds to be excessive blow-by-blow details about chemical minutia. It almost seems as if the book was written to document for some future civilization, the long forgotten research done in this generation on enteric neurology.
The last two chapters get back to readable English and summarize why he and other scientists do the work that they do.
March 28, 2015
This was a good book. The first half was very educational and really written for the non-scientist. The second half, however, started to drag. I suppose that there is really not a lot you can do to make the descriptions of cell migrations and genetic mutations readily accessible to the common folk. But he does his best. I was uncomfortable reading about how bowels were segregated from the animals that once housed them and being reminded over and over again that scientific research of this sort is done on live or once live animals. I have a good mental knowledge that this happens but, like seeing or reading about where my hamburgers come from, I prefer to remain oblivious to the details. He does, however, dedicate the last two pages of the book to justifying the animal experiments. And, yep, it fits with my good mental knowledge. But still. Allow me to live in my fairy tale world!
The early part of the book was so hopeful and encouraging to those of us who suffer from gastrointestinal disorders and diseases. It was extremely informative and gave me a glimpse into what lies right around the corner to help us all out.
Good book.
The early part of the book was so hopeful and encouraging to those of us who suffer from gastrointestinal disorders and diseases. It was extremely informative and gave me a glimpse into what lies right around the corner to help us all out.
Good book.
August 28, 2014
Le ricerche sul Sistema Nervoso enterico risalgono agli anni '50, ma solo dagli '80, dopo un lungo periodo di disinteresse da parte della ricerca mondiale, alcuni scienziati, tra cui l'autore, riprendono gli studi affermando che nel nostro addome esiste un altro cervello.
Il libro racconta in termini cronologici le scoperte, prima di un Sistema Nervoso enterico, separato dall'altro a cui normalmente si fa riferimento nelle sue componenti somatiche ed autonome, poi quella degli specifici neurotrasmettitori, in particolare la serotonina, che agiscono dal momento in cui deglutiamo il cibo a quando espelliamo le scorie, anche se, in certi tratti, i sue Sistemi si integrano nelle diverse funzioni.
Le origini dei due cervelli sono ben espresse nel capitolo dello sviluppo dell'ectoderma nei foglietti embrionali.
Come lo stesso Gershon afferma, non è stato quello digerente l'apparato più studiato e le scoperte vanno avanti cercando di recuperare il tempo perduto. Molte volte, infatti, le patologie degli organi interessati sono state imputate a problemi psicologici mentre, spesso, sono determinate da disfunzioni di varia origine che colpiscono una percentuale piuttosto alta della popolazione.
Il libro è molto interessante, l'autore è anche ironico e gradevole da leggere. Un po' meno facile da seguire l'iter della ricerca che è molto dettagliata, ma di certo valida per l'aspetto scientifico con le classiche situazioni di serendipity.
Personalmente ho sostenuto l'esame di splancnologia nel '78 e fisiologia nel '79 e del Sistema Nervoso enterico non c'era traccia, quindi per me è stata una lettura molto interessante e una valida occasione di aggiornamento.
Il libro racconta in termini cronologici le scoperte, prima di un Sistema Nervoso enterico, separato dall'altro a cui normalmente si fa riferimento nelle sue componenti somatiche ed autonome, poi quella degli specifici neurotrasmettitori, in particolare la serotonina, che agiscono dal momento in cui deglutiamo il cibo a quando espelliamo le scorie, anche se, in certi tratti, i sue Sistemi si integrano nelle diverse funzioni.
Le origini dei due cervelli sono ben espresse nel capitolo dello sviluppo dell'ectoderma nei foglietti embrionali.
Come lo stesso Gershon afferma, non è stato quello digerente l'apparato più studiato e le scoperte vanno avanti cercando di recuperare il tempo perduto. Molte volte, infatti, le patologie degli organi interessati sono state imputate a problemi psicologici mentre, spesso, sono determinate da disfunzioni di varia origine che colpiscono una percentuale piuttosto alta della popolazione.
Il libro è molto interessante, l'autore è anche ironico e gradevole da leggere. Un po' meno facile da seguire l'iter della ricerca che è molto dettagliata, ma di certo valida per l'aspetto scientifico con le classiche situazioni di serendipity.
Personalmente ho sostenuto l'esame di splancnologia nel '78 e fisiologia nel '79 e del Sistema Nervoso enterico non c'era traccia, quindi per me è stata una lettura molto interessante e una valida occasione di aggiornamento.
January 31, 2017
If you are like me, and interested in digging deeper into understanding (1) the digestive system (2) why our intestines make well over 80% of our serotonin and what it could be used for (in the digestive system AND messaging to the brain) (3) the enteric nervous system (our gut has its own brain that works independently and even overrides our "real" brain) and (4) the history behind how the new field of neurogastroenterology came about, and how the research was done and the discoveries were made to support this field THEN THIS BOOK IS FOR YOU!
It is incredibly dense at times, though, especially when talking about the experiments/research. I am NOT well versed in chemistry, biochemistry, or biology YET so I took my sweet time trying to follow along and for the MOST part I was able to with a lot of concentration, but eventually when he got to explaining all the different serotonin receptors and how they figured out which ones did what and what antagonists did what and what that showed, I just wasn't able to hold on.
But for all the crazy-hard science stuff, the writing style of this book was actually amusing and fun even at times.
It is incredibly dense at times, though, especially when talking about the experiments/research. I am NOT well versed in chemistry, biochemistry, or biology YET so I took my sweet time trying to follow along and for the MOST part I was able to with a lot of concentration, but eventually when he got to explaining all the different serotonin receptors and how they figured out which ones did what and what antagonists did what and what that showed, I just wasn't able to hold on.
But for all the crazy-hard science stuff, the writing style of this book was actually amusing and fun even at times.
June 23, 2015
How could you help but admire a physician scientist who describes the bowel as a "primitive, slimy, snakelike thing that...slithers when it moves," yet professes to love this organ? Right from the start, you're know you’re in for a fascinating story. And Dr. Gerson doesn't disappoint. His passion, knowledge and enthusiasm bring vitality to a potentially dry subject. The second brain is the enteric nervous system - a hundred million neurons located along the sides of the single, long tube that automatically pushes food from the mouth to anus, digesting, absorbing and eliminating along the way. It does this independently of the brain in our head. The amazing gut includes the mouth, pharynx, esophagus, stomach, small intestine and large intestine. But the gut is far more complex than digestion. Dr. Gerson also explains the gut-brain connection, why emotions affect the gut, and how gut problems can lead to cloudy thinking. There's a lot of detail on scientific experiments, but overall a most enjoyable read.
June 12, 2012
Gershon is a pioneer in the understanding of the gut, the colon, and all the other parts of our bodies that most of us would rather not think about. But we should: it turns out that we have more neurons in our gut -- yes, neurons, like in our brains -- than a cat has in its brain. Our tummies are, in some weird sense, smarter than cats. Gershon explores this mystery -- if the gut is thinking, what is it thinking about? -- and many others, focusing especially on the diseases of the gut and colon. His writing is lively, opinionated, and absorbing, much like the colons he studies. Not for squeamish readers, but great reading for anyone who wants to understand another piece of the mystery that is humankind.
June 30, 2007
Your gut has its own intrinsic nervous system. If you were to cut the vagus nerves (that run between the brain and the bowel), the enteric nervous system would still go on functioning from stomach to colon.
This dude knows his stuff and really breaks it all down.
This dude knows his stuff and really breaks it all down.
November 2, 2023
The Second Brain is a comprehensive exploration of the gut's enteric nervous system and its profound role in our health and well-being.
Gastric issues and the captivating domain of gut health have long piqued both medical experts and inquisitive minds. Often hailed as our second brain, the gut’s role goes well beyond digestion, extending into the realms of mental health and overall well-being. As gastrointestinal ailments and functional bowel disorders affect a growing number of individuals, understanding the complexities of this essential system becomes paramount.
In this review, we delve into The Second Brain by Dr. Michael D. Gershon, an eminent figure in gastrointestinal research. This book takes us on a journey through the enigmatic enteric nervous system, a frequently overlooked yet vital component of our health.
Author’s background
Dr. Michael D. Gershon, MD, holds the position of Chairman at the Department of Anatomy and Cell Biology within Columbia University’s College of Physicians and Surgeons at the Columbia-Presbyterian Medical Center in New York City.
Throughout his three decades of dedicated research, Dr. Gershon has focused on comprehending the workings of the human gastrointestinal system, encompassing the stomach, oesophagus, small intestine, and colon. His extensive investigations have led to an astounding revelation: the existence of neural cells within the gut that function as a quasi-brain.
What is the book about?
The Second Brain by Michael D. Gershon is a captivating exploration of the enteric nervous system, often referred to as the “second brain.” In this book, Gershon dives into the previously overlooked and mysterious realm of the gut’s intrinsic nervous system, unveiling its inner workings and its crucial role in our overall health and well-being. Organised into three distinct parts, the book covers the following key subjects:
1. Unveiling the notion of a second brain residing in the gut.
2. Illuminating the structure and functionality of the nervous system.
3. Investigating the intricate processes of digestion and nutrient absorption.
4. Identifying potential threats that can arise within the digestive system.
5. Examining the collaborative efforts between the second brain and the immune system to defend against microbial intruders.
6. Emphasising the potential advantages that a deeper comprehension of the second brain holds for millions of individuals, particularly the 40% of adults grappling with functional bowel disorders.
Three key takeaways from The Second Brain
1. Gut as the second brain
Michael D. Gershon presents a profound exploration of the gut as the second brain. Gershon delves into the history of this rediscovery, highlighting the work of pioneers like Bayliss and Starling, who established the existence of the enteric nervous system in the gut. This intrinsic nervous system, often overlooked in other organs, exhibits remarkable properties, including the ability to initiate reflexes independently.
Through experiments like Trendelenburg’s, it became evident that the gut’s intrinsic nervous system possesses brain-like capabilities. This revelation reshapes our understanding of the gut’s significance and its intricate neural network, shedding light on the remarkable second brain that plays a pivotal role in our bodily functions.
2. Nervous-digestive systems connection
The digestive system’s top and bottom ends, controlled by the brain, play a crucial role in determining bowel function, and this connection between the brain and gut can be influenced by mental conditions. Various psychiatric illnesses, like eating disorders and personality disorders, can manifest with enteric symptoms, highlighting the strong connection between mental health and gastrointestinal function.
While it’s commonly believed that thoughts can affect gut behaviour, it’s essential to recognise that enteric illness can originate independently within the enteric nervous system, not solely due to mental influence.
Understanding the intricacies of the enteric nervous system and its role in gastrointestinal health is essential, especially in addressing conditions like functional bowel disease, where symptoms can be debilitating yet often lack a clear pathological link. While previous limitations in studying the enteric nervous system have impeded progress, recent advancements in the field provide hope for identifying specific diseases and developing effective therapies, potentially improving the lives of those affected by functional bowel diseases.
3. The role of the colon in the development of the nervous system
Delves into the fascinating evolutionary and physiological aspects of the colon. It highlights how the colon likely evolved as a mechanism to help land animals conserve water through the process of salt removal, ultimately aiding in water absorption.
The book discusses the presence of symbiotic bacteria in the colon and the role of diarrhoea in cleansing the colon of pathogenic bacteria. Additionally, it explores groundbreaking research on congenital megacolon, revealing insights into the formation of the enteric nervous system in mice and the importance of neural crest-derived cells. This book provides a comprehensive understanding of the colon’s function, evolution, and its vital role in the development of the enteric nervous system.
Strengths and weaknesses, according to readers’ reviews
Strengths:
• The book excels in providing in-depth and well-written biological explanations, covering structural, neurological, and biochemical aspects of gut function, making it a valuable resource for those seeking detailed scientific knowledge.
• The author skillfully injects intellectual humour throughout the book, adding an engaging and lighthearted touch to the dense biological content.
• For readers interested in delving deep into the subject, the book offers a wealth of information, including extensive coverage of chemical names for enzymes and neurotransmitters in the gut.
Weaknesses:
• The abundance of biological terminology and dense scientific substance may make the book less accessible to a broader audience, potentially alienating readers seeking a more approachable and user-friendly exploration of the topic.
• The book focuses heavily on scientific theory and research but may leave readers wanting more real-world applications or insights into how the knowledge presented can be practically applied to address gastrointestinal disease or mental health concerns.
Best quotes from The Second Brain
“Surveys have shown that over 40 percent of patients who visit internists do so for gastrointestinal problems. Half of those have “functional” complaints.”
“On the other hand, unlike the skin, the intestinal lining has also to participate in the critical processes of digestion and absorption. Digestion is the term for the variety of means by which the complex and often very large molecules in food are converted to simpler and smaller molecules that can then be moved from the lumen of the gut into the body. Absorption is the term for the transport of the products of digestion across the lining of the bowel to reach blood and lymph vessels in the wall of the intestine.”
“When I learned that over 95 percent of the body’s serotonin is made in the bowel, therefore, I decided that the organ had promise. In fact, I now know that my original concept of a “simple” nervous system was wrong. A simple nervous system is an oxymoron, like jumbo shrimp; nevertheless, the enteric nervous system, the nervous system of the gut, is simpler than the brain, and its study has served to keep me off the streets.”
Final takeaway
The Second Brain by Dr. Michael D. Gershon offers a captivating exploration of the enteric nervous system, shedding light on the remarkable second brain residing in our gut. While the book excels in providing comprehensive biological explanations and injects intellectual humour into its content, it may be too densely packed with scientific terminology for a general readership. However, it serves as an invaluable resource for those seeking an in-depth understanding of the gut’s intricate neural network. Readers with a strong interest in gastrointestinal science and neurobiology will find this book a valuable addition to their library, offering profound insights into the fascinating world of the gut’s second brain.
Gastric issues and the captivating domain of gut health have long piqued both medical experts and inquisitive minds. Often hailed as our second brain, the gut’s role goes well beyond digestion, extending into the realms of mental health and overall well-being. As gastrointestinal ailments and functional bowel disorders affect a growing number of individuals, understanding the complexities of this essential system becomes paramount.
In this review, we delve into The Second Brain by Dr. Michael D. Gershon, an eminent figure in gastrointestinal research. This book takes us on a journey through the enigmatic enteric nervous system, a frequently overlooked yet vital component of our health.
Author’s background
Dr. Michael D. Gershon, MD, holds the position of Chairman at the Department of Anatomy and Cell Biology within Columbia University’s College of Physicians and Surgeons at the Columbia-Presbyterian Medical Center in New York City.
Throughout his three decades of dedicated research, Dr. Gershon has focused on comprehending the workings of the human gastrointestinal system, encompassing the stomach, oesophagus, small intestine, and colon. His extensive investigations have led to an astounding revelation: the existence of neural cells within the gut that function as a quasi-brain.
What is the book about?
The Second Brain by Michael D. Gershon is a captivating exploration of the enteric nervous system, often referred to as the “second brain.” In this book, Gershon dives into the previously overlooked and mysterious realm of the gut’s intrinsic nervous system, unveiling its inner workings and its crucial role in our overall health and well-being. Organised into three distinct parts, the book covers the following key subjects:
1. Unveiling the notion of a second brain residing in the gut.
2. Illuminating the structure and functionality of the nervous system.
3. Investigating the intricate processes of digestion and nutrient absorption.
4. Identifying potential threats that can arise within the digestive system.
5. Examining the collaborative efforts between the second brain and the immune system to defend against microbial intruders.
6. Emphasising the potential advantages that a deeper comprehension of the second brain holds for millions of individuals, particularly the 40% of adults grappling with functional bowel disorders.
Three key takeaways from The Second Brain
1. Gut as the second brain
Michael D. Gershon presents a profound exploration of the gut as the second brain. Gershon delves into the history of this rediscovery, highlighting the work of pioneers like Bayliss and Starling, who established the existence of the enteric nervous system in the gut. This intrinsic nervous system, often overlooked in other organs, exhibits remarkable properties, including the ability to initiate reflexes independently.
Through experiments like Trendelenburg’s, it became evident that the gut’s intrinsic nervous system possesses brain-like capabilities. This revelation reshapes our understanding of the gut’s significance and its intricate neural network, shedding light on the remarkable second brain that plays a pivotal role in our bodily functions.
2. Nervous-digestive systems connection
The digestive system’s top and bottom ends, controlled by the brain, play a crucial role in determining bowel function, and this connection between the brain and gut can be influenced by mental conditions. Various psychiatric illnesses, like eating disorders and personality disorders, can manifest with enteric symptoms, highlighting the strong connection between mental health and gastrointestinal function.
While it’s commonly believed that thoughts can affect gut behaviour, it’s essential to recognise that enteric illness can originate independently within the enteric nervous system, not solely due to mental influence.
Understanding the intricacies of the enteric nervous system and its role in gastrointestinal health is essential, especially in addressing conditions like functional bowel disease, where symptoms can be debilitating yet often lack a clear pathological link. While previous limitations in studying the enteric nervous system have impeded progress, recent advancements in the field provide hope for identifying specific diseases and developing effective therapies, potentially improving the lives of those affected by functional bowel diseases.
3. The role of the colon in the development of the nervous system
Delves into the fascinating evolutionary and physiological aspects of the colon. It highlights how the colon likely evolved as a mechanism to help land animals conserve water through the process of salt removal, ultimately aiding in water absorption.
The book discusses the presence of symbiotic bacteria in the colon and the role of diarrhoea in cleansing the colon of pathogenic bacteria. Additionally, it explores groundbreaking research on congenital megacolon, revealing insights into the formation of the enteric nervous system in mice and the importance of neural crest-derived cells. This book provides a comprehensive understanding of the colon’s function, evolution, and its vital role in the development of the enteric nervous system.
Strengths and weaknesses, according to readers’ reviews
Strengths:
• The book excels in providing in-depth and well-written biological explanations, covering structural, neurological, and biochemical aspects of gut function, making it a valuable resource for those seeking detailed scientific knowledge.
• The author skillfully injects intellectual humour throughout the book, adding an engaging and lighthearted touch to the dense biological content.
• For readers interested in delving deep into the subject, the book offers a wealth of information, including extensive coverage of chemical names for enzymes and neurotransmitters in the gut.
Weaknesses:
• The abundance of biological terminology and dense scientific substance may make the book less accessible to a broader audience, potentially alienating readers seeking a more approachable and user-friendly exploration of the topic.
• The book focuses heavily on scientific theory and research but may leave readers wanting more real-world applications or insights into how the knowledge presented can be practically applied to address gastrointestinal disease or mental health concerns.
Best quotes from The Second Brain
“Surveys have shown that over 40 percent of patients who visit internists do so for gastrointestinal problems. Half of those have “functional” complaints.”
“On the other hand, unlike the skin, the intestinal lining has also to participate in the critical processes of digestion and absorption. Digestion is the term for the variety of means by which the complex and often very large molecules in food are converted to simpler and smaller molecules that can then be moved from the lumen of the gut into the body. Absorption is the term for the transport of the products of digestion across the lining of the bowel to reach blood and lymph vessels in the wall of the intestine.”
“When I learned that over 95 percent of the body’s serotonin is made in the bowel, therefore, I decided that the organ had promise. In fact, I now know that my original concept of a “simple” nervous system was wrong. A simple nervous system is an oxymoron, like jumbo shrimp; nevertheless, the enteric nervous system, the nervous system of the gut, is simpler than the brain, and its study has served to keep me off the streets.”
Final takeaway
The Second Brain by Dr. Michael D. Gershon offers a captivating exploration of the enteric nervous system, shedding light on the remarkable second brain residing in our gut. While the book excels in providing comprehensive biological explanations and injects intellectual humour into its content, it may be too densely packed with scientific terminology for a general readership. However, it serves as an invaluable resource for those seeking an in-depth understanding of the gut’s intricate neural network. Readers with a strong interest in gastrointestinal science and neurobiology will find this book a valuable addition to their library, offering profound insights into the fascinating world of the gut’s second brain.
February 11, 2018
Secondo cervello, una nuova concezione dell'uomo. Il Prof. Gershon ci presenta una rivoluzione copernicana nella concezione dell'organismo umano: la visione del corpo dominato dalla mente lascia il posto a una visione integrata, dove l'intestino è un secondo cervello. La caduta dell'impero retto dal cervello unico sovrano apre la via a un sistema pluricentrico. La storia di questa scoperta è anche la conferma di alcune conoscenze tradizionali: l'affermazione neurobiologica della stretta connessione tra mente e corpo, in particolare tra cervello e intestino.
Nella storia della medicina moderna, l'intestino per molto tempo è stato considerato una struttura periferica dell'organismo, deputata a svolgere funzioni se non marginali, sicuramente secondarie rispetto a più nobili attività svolte da altri organi quali il cervello e il cuore.
La radice di questo pregiudizio è rintracciabile nell'antica idea platonica del corpo visto come composto dal soma — il corpo inerte del morto — vivificato dalla psiche — l' anima — che conferisce vita e intelligenza al tutto. Più tardi Cartesio si sentirà in obbligo di sottolineare la predominanza di una res cogitans deputata a controllare e dirigere la passiva res extensa, inerte. Nel corso della storia della medicina, in questa visione che assegna al corpo il ruolo di passivo esecutore di ordini impartiti dall'alto, nel ruolo di imperatore si alterneranno differenti organi. I principali coordinatori dell'organismo saranno essenzialmente due: cuore e cervello. L'intestino non sarà mai coinvolto in queste guerre di palazzo e nei secoli resterà relegato nell'oscuro ruolo di cloaca dei palazzi imperiali. Solo la medicina cinese azzarderà una sua promozione a Ministro delle Dismissioni, ma ciò non lo avvicinerà di un passo a quella stanza dei bottoni da cui gli organi imperatori coordinano le attività funzionali dell'intero organismo. È pur vero che in questo lungo periodo le menti più eccelse avevano dovuto constatare come le più nobili passioni o le idee più audaci potessero essere ridotte al nulla da banali mal di pancia. Come afferma Gershon, «Nessuno riesce a pensare seriamente se la sua mente è concentrata sulla toilette». Tuttavia queste insurrezioni coliche non avevano mai dato origine a riflessioni serie sui rapporti intercorrenti tra cuore, mente, cervello e intestino.
La scoperta dell'intestino «sede indipendente di integrazione ed elaborazione neurale» costituisce, quindi, un'importante innovazione, che ha rilevanti implicazioni a livello della valutazione delle relazioni organismo/intestino, ma anche, e soprattutto, a livello di un mutamento di concezione della struttura dell'uomo, di cui probabilmente siamo solo agli albori. Ma non basta. Le importanti scoperte di Gershon portano a intravedere nell'intestino non un regno oscuro e caotico, contrapposto all'impero chiaro e ordinato del cervello, bensì un altro ordine, un altro tipo di strutturazione, non per questo barbara. Fornisce gli elementi di base per capire come l'attività dell'imperatore, cuore o cervello che sia, venga condizionata dagli influssi di questo regno periferico, non meno di quanto essa condizioni la vita e il funzionamento dell'intestino stesso. In questo senso, uno dei meriti principali dell'autore è proprio la sua capacità di far emergere con chiarezza come l'uomo non possa essere paragonato a una macchina o a un robot perché, in realtà, è una struttura complessa, ove tutte le parti, in costante contatto tra loro, contribuiscono in maniera paritetica allo sviluppo e al mantenimento dell'unità dell'essere, nella salute come nella malattia.
Nella storia della medicina moderna, l'intestino per molto tempo è stato considerato una struttura periferica dell'organismo, deputata a svolgere funzioni se non marginali, sicuramente secondarie rispetto a più nobili attività svolte da altri organi quali il cervello e il cuore.
La radice di questo pregiudizio è rintracciabile nell'antica idea platonica del corpo visto come composto dal soma — il corpo inerte del morto — vivificato dalla psiche — l' anima — che conferisce vita e intelligenza al tutto. Più tardi Cartesio si sentirà in obbligo di sottolineare la predominanza di una res cogitans deputata a controllare e dirigere la passiva res extensa, inerte. Nel corso della storia della medicina, in questa visione che assegna al corpo il ruolo di passivo esecutore di ordini impartiti dall'alto, nel ruolo di imperatore si alterneranno differenti organi. I principali coordinatori dell'organismo saranno essenzialmente due: cuore e cervello. L'intestino non sarà mai coinvolto in queste guerre di palazzo e nei secoli resterà relegato nell'oscuro ruolo di cloaca dei palazzi imperiali. Solo la medicina cinese azzarderà una sua promozione a Ministro delle Dismissioni, ma ciò non lo avvicinerà di un passo a quella stanza dei bottoni da cui gli organi imperatori coordinano le attività funzionali dell'intero organismo. È pur vero che in questo lungo periodo le menti più eccelse avevano dovuto constatare come le più nobili passioni o le idee più audaci potessero essere ridotte al nulla da banali mal di pancia. Come afferma Gershon, «Nessuno riesce a pensare seriamente se la sua mente è concentrata sulla toilette». Tuttavia queste insurrezioni coliche non avevano mai dato origine a riflessioni serie sui rapporti intercorrenti tra cuore, mente, cervello e intestino.
La scoperta dell'intestino «sede indipendente di integrazione ed elaborazione neurale» costituisce, quindi, un'importante innovazione, che ha rilevanti implicazioni a livello della valutazione delle relazioni organismo/intestino, ma anche, e soprattutto, a livello di un mutamento di concezione della struttura dell'uomo, di cui probabilmente siamo solo agli albori. Ma non basta. Le importanti scoperte di Gershon portano a intravedere nell'intestino non un regno oscuro e caotico, contrapposto all'impero chiaro e ordinato del cervello, bensì un altro ordine, un altro tipo di strutturazione, non per questo barbara. Fornisce gli elementi di base per capire come l'attività dell'imperatore, cuore o cervello che sia, venga condizionata dagli influssi di questo regno periferico, non meno di quanto essa condizioni la vita e il funzionamento dell'intestino stesso. In questo senso, uno dei meriti principali dell'autore è proprio la sua capacità di far emergere con chiarezza come l'uomo non possa essere paragonato a una macchina o a un robot perché, in realtà, è una struttura complessa, ove tutte le parti, in costante contatto tra loro, contribuiscono in maniera paritetica allo sviluppo e al mantenimento dell'unità dell'essere, nella salute come nella malattia.
March 10, 2022
Pretty dry. Learned lots.
January 18, 2019
Complimenti all'autore per la competenza in fatto di ricerca, siamo davanti a un luminare. Altro complimento lo merita lo stile, perché la tematica pesante è spesso alleggerita con commenti o esemplificazioni ironiche e anche divertenti. Certe parti, però, restano decisamente tecniche, specialmente nell'ultima parte del testo, in cui ho dovuto riesumare alcune conoscenze di biologia cellulare del liceo per non perdermi. Detto questo, è un libro da consigliare a chi ha interesse a capire come funziona il sistema digestivo, e a chi vuole sapere qualcosa di più sul lavoro di ricercatore.
February 2, 2016
A good, readable account of how a top-notch scientist made important discoveries about the role of the enteric nervous system.
Written before the explosion of understanding of the human microbiome, he includes excellent details of each of the parts of the gastric system and how the nerves function, right down to the level of seronotin, but much of this is obsolete now that the role of microbes is becoming known.
Written before the explosion of understanding of the human microbiome, he includes excellent details of each of the parts of the gastric system and how the nerves function, right down to the level of seronotin, but much of this is obsolete now that the role of microbes is becoming known.
March 2, 2017
Well-presented history of the author's extensive basic research into the neuro-anatomy of the human digestive system. Quite detailed and fascinating. Dr. Gershon both comes across as an expert and as an unpretentious lifelong student, a generous mentor and collaborator. I sought out the book as a result of a footnote in something else I read. It is an example of the serendipitous education I am pursuing in my retirement.
January 20, 2017
This amazing scientist using storytelling technique to disclose well-kept secrets of the nervous system in the gut. This essential information will hopefully eventually seep into mainstream medicine, where it will benefit the masses suffering from gut disturbances, many of which are an unwitting resultant from pharmaceuticals.
Read
December 15, 2008I confess, I ended up skimming quite a bit of the second half because it was due back at the library. Interesting, but I don't really have the science/medical background to find it enthralling. But know I know that I have an enteric nervous system and it produces a lot of serotonin.
July 9, 2013
Fascinating stuff. Very technical, but I think that's a positive attribute in a science book.
September 25, 2015
Dr. Gershon is brilliant in both conducting research and writing about it. This book is vital for all health care professionals, educators, and persons interested in health.
February 16, 2016
Questo e` un signor libro di divulgazione.
January 8, 2017
Fascinating! Makes so much sense.
July 13, 2017
Excellent book. Wish I knew more about human physiology and bio to follow it all.
April 1, 2025
Details his research
“The critical function of endothelin-3 is to dampen the reception that the colon provides for the neural crest derived cells.
The population of neural-crest derived cells is multi potent- the fates of the population are not determined before its cells leave the neural crest but depend on signals these cells receive from the micro environment they find either along their migratory routes or within the target organs that they ultimately colonize.
There are multiple (at least two) lineages of precursors contributing to the development of the enteric nervous system. Lineage and the enteric microenvironment both sculpt the enteric nervous system.”
Neural crest cells follow defined pathways in the embryo, which lead to the bowel from specific regions of the neural crest. If you put almost any neural crest cell on this path, it winds up in the gut.
Hi shut receives crest-derived cells from both vagal and sacral sources.
The enteric nervous system Is formed from neural crest cells.
The enteric nervous system is formed by cells that migrate to the bowel only from three very specific regions of the neural crest. Truncal crest colonizes only the esophagus and the adjacent stomach. Vagal crest colonizes the entire bowel below the esophagus and adjacent stomach. Sacral crest colonizes only the guy below the umbilicus.
Interstitial cells of cajal act as pacemakers that set the slow electrical rhythm that characterizes sheets of interstitial smooth muscle.”
Messages destined for enteric nervous system are registered by 5HT1P receptors while those destined for the brain are related by 5HT3 receptors.
Serotonin is released by mechanical stimulation of the intestinal mucosa…serotonin initiates the peristaltic reflex and serotonin works by stimulating mucosal processes of submucosal sensory nerve cells.
Fatty acids anywhere in the intestinal lumen turns on Ileana brake. Bio
The serotonin-containing entero-pancreatic nerves exist to oppose the activation of pancreatic nerve cells by acetylcholine.
The nerve cells in the myenteric plexus of the colon innervate the ganglion (inferior mesenteric) that provides the end of the colon and rectum with sympathetic innervation. Enteric nervous system can cancel messages from the brain that it does not want the sympathetic nerves to deliver.
Pancreatitis involves the horror of auto digestion or self-cannibalism
Pancreatic proenzymes become activated by enterokinases in the small intestinal lumen
The liver transports the waste products that cannot be filtered by the kidney to the bile. The distinctive green color of bile comes from molecular detritus from destruction of RBCs.
The plan of the bowel appears to have incorporated a fail-safe redundancy of protective mechanisms when we the costs of failure are intolerable.”
Serotonin was released when pressure was placed upon cells in the lining of the bowel, and that this serotonin stimulated intrinsic enteric sensory nerves to start the peristaltic reflex.
Serotonin is manufactured and stored in the bowel. Serotonin is oreferentially stored in the enteric nerves. Nerves release serotonin when stimulated. Serotonin exerts the same effect on the bowel as does the stimulation of enteric nerves.
A herd instinct often grips the imaginations of scientists. Like lemmings, we are prone to charge over cliffs when a large enough pack of us moves in that direction.”
“The critical function of endothelin-3 is to dampen the reception that the colon provides for the neural crest derived cells.
The population of neural-crest derived cells is multi potent- the fates of the population are not determined before its cells leave the neural crest but depend on signals these cells receive from the micro environment they find either along their migratory routes or within the target organs that they ultimately colonize.
There are multiple (at least two) lineages of precursors contributing to the development of the enteric nervous system. Lineage and the enteric microenvironment both sculpt the enteric nervous system.”
Neural crest cells follow defined pathways in the embryo, which lead to the bowel from specific regions of the neural crest. If you put almost any neural crest cell on this path, it winds up in the gut.
Hi shut receives crest-derived cells from both vagal and sacral sources.
The enteric nervous system Is formed from neural crest cells.
The enteric nervous system is formed by cells that migrate to the bowel only from three very specific regions of the neural crest. Truncal crest colonizes only the esophagus and the adjacent stomach. Vagal crest colonizes the entire bowel below the esophagus and adjacent stomach. Sacral crest colonizes only the guy below the umbilicus.
Interstitial cells of cajal act as pacemakers that set the slow electrical rhythm that characterizes sheets of interstitial smooth muscle.”
Messages destined for enteric nervous system are registered by 5HT1P receptors while those destined for the brain are related by 5HT3 receptors.
Serotonin is released by mechanical stimulation of the intestinal mucosa…serotonin initiates the peristaltic reflex and serotonin works by stimulating mucosal processes of submucosal sensory nerve cells.
Fatty acids anywhere in the intestinal lumen turns on Ileana brake. Bio
The serotonin-containing entero-pancreatic nerves exist to oppose the activation of pancreatic nerve cells by acetylcholine.
The nerve cells in the myenteric plexus of the colon innervate the ganglion (inferior mesenteric) that provides the end of the colon and rectum with sympathetic innervation. Enteric nervous system can cancel messages from the brain that it does not want the sympathetic nerves to deliver.
Pancreatitis involves the horror of auto digestion or self-cannibalism
Pancreatic proenzymes become activated by enterokinases in the small intestinal lumen
The liver transports the waste products that cannot be filtered by the kidney to the bile. The distinctive green color of bile comes from molecular detritus from destruction of RBCs.
The plan of the bowel appears to have incorporated a fail-safe redundancy of protective mechanisms when we the costs of failure are intolerable.”
Serotonin was released when pressure was placed upon cells in the lining of the bowel, and that this serotonin stimulated intrinsic enteric sensory nerves to start the peristaltic reflex.
Serotonin is manufactured and stored in the bowel. Serotonin is oreferentially stored in the enteric nerves. Nerves release serotonin when stimulated. Serotonin exerts the same effect on the bowel as does the stimulation of enteric nerves.
A herd instinct often grips the imaginations of scientists. Like lemmings, we are prone to charge over cliffs when a large enough pack of us moves in that direction.”
Read
October 5, 2021Good Reads wants me to do a review. I read this a number of years ago, so remember that as you read.
I got diagnosed with some crummy gut conditions and I went looking for answers. This book was very helpful, even if it had already become a tad dated. No new book had come along to take its place.
The book not only discusses the mechanics and chemistry of digestion and the digestive tract, it discusses the evolution of thinking about digestion and the digestive tract. It acknowledges the "it's all in your head, little lady, just go home and thank your blessings" kind of attitude about apparently psychosomatic issues reported by patients, esp. women. This still prevails today, but not as commonly. The author essentially apologizes on behalf of the medical profession.
The author was part of a research team that focused on digestive chemistry which came to recognize the heavy presence of "brain chemicals" in the gut, esp. serotonin. They worked their way from being considered the "off the wall" presentation at annual conferences (allocated to obscure rooms and times in the schedules) to being in large well-attended venues and winning over some old guard researchers who had mocked them earlier. It is a perfect example of the process described in Thomas Kuhn's book on scientific revolutions, which pioneered the term "paradigm shift."
The author gives good real world examples that put a human face on patients and researchers. I still recall his account of working with a child with Hashimoto's Disease whose body could not complete a BM and required physical manipulation. He describes the problems with sensitivity and tact and sufficient realistic details to show both his empathy and his science dedication.
Much of the book did not directly help me understand being a victim of a surgical mistake, but enough of the info was pertinent that it laid the groundwork for more reading about the importance of the nerve system in generating stimulating signals from the brain to the gut but also the feedback from the gut to the brain that can override so many other body system signals. This showed me how to rethink my own situation and how not to believe some of my own nervous signaling. The knowledge helps guide me to this day.
I got diagnosed with some crummy gut conditions and I went looking for answers. This book was very helpful, even if it had already become a tad dated. No new book had come along to take its place.
The book not only discusses the mechanics and chemistry of digestion and the digestive tract, it discusses the evolution of thinking about digestion and the digestive tract. It acknowledges the "it's all in your head, little lady, just go home and thank your blessings" kind of attitude about apparently psychosomatic issues reported by patients, esp. women. This still prevails today, but not as commonly. The author essentially apologizes on behalf of the medical profession.
The author was part of a research team that focused on digestive chemistry which came to recognize the heavy presence of "brain chemicals" in the gut, esp. serotonin. They worked their way from being considered the "off the wall" presentation at annual conferences (allocated to obscure rooms and times in the schedules) to being in large well-attended venues and winning over some old guard researchers who had mocked them earlier. It is a perfect example of the process described in Thomas Kuhn's book on scientific revolutions, which pioneered the term "paradigm shift."
The author gives good real world examples that put a human face on patients and researchers. I still recall his account of working with a child with Hashimoto's Disease whose body could not complete a BM and required physical manipulation. He describes the problems with sensitivity and tact and sufficient realistic details to show both his empathy and his science dedication.
Much of the book did not directly help me understand being a victim of a surgical mistake, but enough of the info was pertinent that it laid the groundwork for more reading about the importance of the nerve system in generating stimulating signals from the brain to the gut but also the feedback from the gut to the brain that can override so many other body system signals. This showed me how to rethink my own situation and how not to believe some of my own nervous signaling. The knowledge helps guide me to this day.
December 25, 2023
Gershon attempts to set out a history of his own work on neurogastroenterology and of the field itself, and explore the science behind his idea of a "second brain". Written less for a lay audience and more for a somewhat technically competent reader (though it sometimes becomes very lay in its writing), the book broadly achieves in exploring the neurology of the GI tract at least through the lens of Gershon's work. The language is easy enough and filled with anecdotes that make it easy to go though despite the technical explanations.
The content itself focuses on the neurostructural and neurochemical structures of the enteric system. Explanations of the ENS, the exploration of the role of serotonin, and the development of thought about the ENS is well documented. Given the lack of content on the neurological basis of the gut, Gershon's book stands out. In understanding the neurostructural and neurochemical basis of the gut, including its evolutionary origins, this is a great piece of work.
However, there are still visible flaws. Chief is that although it is presented as an exploration of the science of the ENS, it is fundamentally only an exploration of work that Gershon has been involved directly or indirectly with. This results in a considerably narrow field of vision. Gershon engages well with counterarguments to his own, with detailed explanations of methodology and results, but arguments outside of his own work rarely find its way in. This even results in some critical errors, such as the minimal reference made to the role of microbiome in the ENS and the stupendous claim that the small intestine is largely sterile.
The strength of the content given is at least at a 4star level, but the narrow perspective and critically, the errors make it difficult to argue the book is as well rated overall. It is still a very useful piece of work, and I'm likely to revisit it for the neurostructural content in particular, but would take the rest with a very cautious disposition.
The content itself focuses on the neurostructural and neurochemical structures of the enteric system. Explanations of the ENS, the exploration of the role of serotonin, and the development of thought about the ENS is well documented. Given the lack of content on the neurological basis of the gut, Gershon's book stands out. In understanding the neurostructural and neurochemical basis of the gut, including its evolutionary origins, this is a great piece of work.
However, there are still visible flaws. Chief is that although it is presented as an exploration of the science of the ENS, it is fundamentally only an exploration of work that Gershon has been involved directly or indirectly with. This results in a considerably narrow field of vision. Gershon engages well with counterarguments to his own, with detailed explanations of methodology and results, but arguments outside of his own work rarely find its way in. This even results in some critical errors, such as the minimal reference made to the role of microbiome in the ENS and the stupendous claim that the small intestine is largely sterile.
The strength of the content given is at least at a 4star level, but the narrow perspective and critically, the errors make it difficult to argue the book is as well rated overall. It is still a very useful piece of work, and I'm likely to revisit it for the neurostructural content in particular, but would take the rest with a very cautious disposition.
October 27, 2021
I lied--I didn't have the stamina to complete this book. I did, however, complete 90%. It was not what I had expected to read.
Dr Gershon is an extraordinarily talented scientist, which he proved through all the history and reasoning that he used in his research, and which he extensively described in this book. Unfortunately, he is very wordy, and loyal to other colleagues beyond belief; he, therefore, tediously described every experiment, every error, every participant, every result, every conclusion, et cetera, et cetera. If you wish to understand how a investigating scientific laboratory works--this is your book. If you only want the specific details of how the bowel is formed, and how it functions, this is the wrong book.
And, finally, the most grievous error is the subtitle of the book: "The Scientific Basis of Gut Instinct" (which was, by the way, the ONLY reason I was reading this book) was not mentioned once, and, therefore, the reason that I didn't slog through the last 30 pages.
In summary, for the person looking for an understanding of laboratory procedure with a specific desire to understand the development and functioning of the gut: this is the book for you. All others I would advise looking for something.
(In addition, since the book is so old [published in 1998--ancient for scientific research], there is no exploration of the gut microbiome. With Dr Gershon's talent for detail and scientific expertise, I would really have loved to have read his thoughts, research, and integration of this most important subject.)
Dr Gershon is an extraordinarily talented scientist, which he proved through all the history and reasoning that he used in his research, and which he extensively described in this book. Unfortunately, he is very wordy, and loyal to other colleagues beyond belief; he, therefore, tediously described every experiment, every error, every participant, every result, every conclusion, et cetera, et cetera. If you wish to understand how a investigating scientific laboratory works--this is your book. If you only want the specific details of how the bowel is formed, and how it functions, this is the wrong book.
And, finally, the most grievous error is the subtitle of the book: "The Scientific Basis of Gut Instinct" (which was, by the way, the ONLY reason I was reading this book) was not mentioned once, and, therefore, the reason that I didn't slog through the last 30 pages.
In summary, for the person looking for an understanding of laboratory procedure with a specific desire to understand the development and functioning of the gut: this is the book for you. All others I would advise looking for something.
(In addition, since the book is so old [published in 1998--ancient for scientific research], there is no exploration of the gut microbiome. With Dr Gershon's talent for detail and scientific expertise, I would really have loved to have read his thoughts, research, and integration of this most important subject.)
August 19, 2019
Another mixed review. On the one hand, it's great to know that the enteric system does have its own, separate nervous system that will continue to work independently even after it's disconnected from the spine. (The former practice for relieving ulcer pain.) Also great to learn that chemicals like SSRIs can improve your digestion by making that brain less neurotic in addition to the one in your skull. I also have an explanation as to why my doctor keeps pushing on my abdomen every time I visit and asking me if it's painful. (Any pain there and going towards the shoulder or back isn't good.) Last but not least, in my opinion, is Gershon's descriptions of how research science is funded and accomplished, including a first-person account on presenting controversial findings at a major conference. (Great to hear I'm not the only one having those feelings.)
Now for the major downside to this book: it's chock full of biochemistry. Don't let the innocuous cover fool you like it did me, it plunges right into some hardcore biology within the first chapter. (I felt like I was back in Biology for Non-Majors as a college freshman.) It alternates with more narrative chapters, but there are plenty of Latin names, abbreviations, and complicated descriptions to strand an intelligent reader if you're not paying very close attention. If you don't mind such things, there's plenty to learn, but I would not recommend this book to laypeople.
Now for the major downside to this book: it's chock full of biochemistry. Don't let the innocuous cover fool you like it did me, it plunges right into some hardcore biology within the first chapter. (I felt like I was back in Biology for Non-Majors as a college freshman.) It alternates with more narrative chapters, but there are plenty of Latin names, abbreviations, and complicated descriptions to strand an intelligent reader if you're not paying very close attention. If you don't mind such things, there's plenty to learn, but I would not recommend this book to laypeople.
December 28, 2018
I really enjoyed this book, especially the first two-thirds. The first part covers the author’s early discoveries relating to serotonin in the intestine and the history of gut research. The second part is an organ by organ tour of the digestive tract. One thing I liked particularly was that he explains a process in an organ (which he does very clearly) and then if there is a medication that works by affecting this part of the system, he explains exactly how it works and what its problems/advantages are. It enabled me to better understand how acid reducers and proton pump inhibitors work, why NSAIDs cause ulcers, why certain anti-depressants cause constipation, etc. The third part of the book details the author’s later molecular researches into the function of the gut. It is very detailed, and I got bogged down a few times, but it gives a very clear picture of the collaborations, competitions and nitty gritty of medical research which was valuable. The author writes with humor and personal anecdotes but doesn’t sacrifice accuracy. One of my favorite books of the year.
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