Your digestive tract has as many brain cells as a cat

Smart as a cat
Credit: Aesthetic Center

“There are over 100 million brain cells in your gut – as many as there are in the head of a cat.”

BBC News – ‘The second brain in our stomachs’
https://www.bbc.com/news/health-18779997

Scientific American – ‘Think Twice: How the Gut's “Second Brain” Influences Mood & Well-Being’
https://www.scientificamerican.com/article/gut-second-brain/

Scientific American – ‘Gut Feelings – the “Second Brain” in Our Gastrointestinal Systems’
https://www.scientificamerican.com/article/gut-feelings-the-second-brain-in-our-gastrointestinal-systems-excerpt/ / stomach dark mystery most of us new research revealing surprising ways our guts exert control over our mood and appetite stomach digestion in action London's Science Museum watched live pictures from my own stomach porridge eaten for breakfast churned broken up exposed to acid pushed out small intestine creamy mush called chyme swallowed miniature camera pill travelling through my digestive system projecting images onto a giant screen stomach complex work control the little brain network of neurons line stomach and your gut 100 million cells in your gut many as there are in the head of a cat little brain complex thinking essential daily grind digesting food mixing contracting absorbing break down food begin extracting nutrients vitamins we need neurons neuron lining our digestive system keep in close contact brain in your skull vagus nerves influence our emotional state experience butterflies in the stomach brain in the stomach talking to the brain in your head get nervous or fearful blood diverted from our gut to our muscles stomach's way of protesting hunger hormones accommodate big meal stomach has to expand size of a fist around 2 litres 40-fold increase stretch receptors stomach told the brain stomach was full time to stop eating hunger signals produced by your stomach far more sophisticated doctors treat grown to 20 stone heart attack lose weight gastric bypass operation reducing size of the stomach smaller the stomach the less you eat surgeon Mr Ahmed Ahmed London's Charing Cross Hospital surgery you're producing changes in various hormones chemical messengers affect hunger levels fullness levels cause the weight loss gastric bypass surgery isolated part stomach produces most ghrelin hormone play a key role in making you feel hungry permanent fall in production of ghrelin new shrunken stomach attached further down his small intestine ileum secretes a different gut hormone PYY responsible for making you feel full normally takes 20 minutes for food to get from the stomach to the ileum causing release of PYY message to the brain I'm full better to eat slowly give stomach chance tell the brain you have had enough before you overeat ileum stomach brain already lost three stone eat a small amount of food and I feel full lose more weight gastric bypass available extreme cases intense interest developing drugs mimic actions PYY brain rules our decision-making process operations our guts very profound effect how we behave big meal third of your blood supply diverted to your guts digest guts human stomach /