Where do we start with digestion? We start from the North, so the Mouth (or we could even say the Brain if we want to get real technical). The second we put food into our mouth we start the mechanical/chemical breakdown process of digestion. We use our teeth to chew and our tongue to push the food around in our mouth (mechanical) and we produce saliva which softens our food and produces enzymes do break down carbohydrates (chemical) so they are more easily digested and absorbed. So we're chewing our food, hopefully slowly, enjoying the tastes and we create a Bolus, this is the chewed up food which when we swallow enters our esophagus and makes it's way down south, to our Stomach.
The stomach (should be) a very acidic place, designed for a normal pH of 1.5-3.0. WOW, it's a good thing our stomach has a mucosa lining to protect us from the strong stomach acid, which if that pH level of acid were to touch our skin it would burn us. At this point the stomach continues the mechanical breakdown of food, a long with a number of chemical activities. The bolus is being churned and broken down, while gastric juices are being secreted from millions of tiny gastric glands located in the mucosal lining of the stomach. The bolus is now being broken down into a sort of paste called Chyme. The chyme is very acidic and now it's time for it to be released into the beginning of the Small Intestine, the Duodenum, say that 5 times fast. Because the chyme is so acidic as it enters the duodenum it triggers the small intestine to secrete mucous and two hormones; secretin and cholecystokinin (CCK). Secretin stimulates the pancreas to release bicarbonate and pancreatic juice and CCk stimulates the gallbladder to release bile.
-Bile is necessary to emulsify and absorb fats
-As part of the pancreatic juice, the pancreas first releases sodium bicarbonate to help raise the pH of chyme and then the enzyme portion of the pancreatic juice is released to complete the chemical digestion of carbohydrates, proteins and fats.
By the time the chyme leaves the duodenum, it's almost completely digested. Now all the absorbable molecules are moved into the jejunum where millions of villi and microvilli (small finger like substances that line the small intestine and absorb the nutrients that pass through) absorb the nutrients into the bloodstream. When they are in the bloodstream they are then carried to the entire body.
Leftover chyme from the small intestine; fibers that are indigestible, bile, water, and sloughed off cells are passed on to the large intestine through a one way valve called the Ileocecal valve.
Now it's the Large Intestines time to shine! Yep, I said shine! Our digestive system is so amazing and such a hard worker it definitely deserves some enthusiastic lingo associated with it.
So here we are at the very Southern end of the digestive system where our large intestine is put to work; recycling water, recycling the waste material, which nourishes the colon cells. It also captures any lost nutrients that are still available and converts the nutrients to vitamins K, B1, B2, B12, and Butyric acid. All while our feces are being formed and then the most exciting part........ELIMINATION! Which we are all familiar with.
Proper digestion is a North to South process as well as Dysfunction of the digestive system. Always look to the North and move your way south.
Brain - Mouth - Bolus - Stomach - Chyme - Small Intestine - Remains - Large Intestine - Feces
This was just a broad over view of the digestive system just to give you a general idea of how it works. This information will come in handy in this blog, a lot of things will coincide with digestion and eventually I can go into more detail of digestion and also the disfunction's of the digestive system.
This is a great post, and you explain everything really well. So, why do people have problems with digesting certain foods?
ReplyDeleteShana that's an awesome question, thank you for asking it. I'm going to do the best to answer it with what I've learned so far. Our bodies need nutrients to run optimally that's what we all have in common but some of us may lack the nutrients that help our support our digestive system and help it run smoothly, this can cause digestive problems. That said, there is not just one straight forward answer, there are many factors as to why a person may have problems digesting certain foods.
DeleteHere are a few reasons as to why this could be happening.
There could be a lack of good gut bacteria/flora (probiotics) which helps with digestion.
If there is not enough acid in the stomach, foods do not get broken down (carbs ferment, fats go rancid and proteins putrefy). So if a person does not have enough stomach acid they could have issues digesting certain foods that someone else wouldn't who had the right amount of stomach acid.
Insufficient Digestive Enzymes is also another factor as to why someone may not be able to break down certain foods.
It may be as simple as a person not chewing that particular food well enough for it to be properly broken down.
They could have poor gallbladder function if they've had a low fat diet for many years making it so they are not able to emulsify and breakdown their fats.
Also it could be that an intolerance to certain foods may have developed from years of poor digestion. Now they are not able to digest those foods properly due to a weakened digestive system.
This really is just a small list of possible reasons and in the future I'd like to do a Blog post on the Dysfunction of the digestive system and go into more depth.
I hope this was a little helpful and I really appreciate your comment and question. Thank you!
Great blog post! You do a great job explaining in such a comprehensive way. Also, great answer to the question above!
ReplyDeleteI loved how you explain the digestive system. It really is something we should be taught from a young age! I know I'll teach my kids this so that they can grow up understanding their digestive system and how it works.
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