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.
