The Small Intestine and Our Digestive Processes
The small intestine is an extremely important tube that is found in our digestive system. Many nutrients and minerals are absorbed here in the small intestine. The small intestine is extremely long in its size, around 10 feet long and 1 inch in diameter.
The length of the small intestine is necessary solely because of nutrient absorption that takes place there. The length is also increased because there are many folds and villi, which help to increase surface area in the small intestine.
The beginning of the small intestine is called the duodenum. The duodenum connects the stomach and the small intestine, two very important parts of the digestive tract. It is the shortest region of the small intestine. The name duodenum literally means “12” and this part of the small intestine has this name because it is the width of about 12 fingers!
The next part of the small intestine is the jejunum. It is around 3 feet long and extends to the ileum. The ileum is the longest and last part of the small intestine, measuring around 6 feet long. The ileum connects the small intestine to the large intestine.
Between the two, there is an ileocecal sphincter, which is a muscular valve that releases digested food into the large intestine.
There is mucosa in the small intestine, and it is adapted to the functions of the small intestine. The mucosal has important functions of absorbing nutrients, vitamins, and minerals. The mucosa contains absorptive cells, and they are the main cells that are responsible for absorption.
Goblet cells are also found in the mucosa of the small intestine, and their role is to secret mucous into the small intestine. The small intestine has the same 4 layers that are found all throughout the digestive tract, but in the small intestine these layers are more specialized.
For example, there are circular folds, which enhance absorption in the duodenum and ileum. Also in the small intestine are villi, which are fingerlike processes that are no longer than 1 mm long. These villi contain capillaries to help absorb nutrients, and also contain lymphatic vessels for waste.
In the small intestine, a large amount of intestinal juice is secreted every day. It is a yellow juice that contains water and mucous and has a pH of around 7.6, making it slightly basic or alkaline.
Intestinal juices are necessary in order for nutrient absorption to take place. Intestinal juices will mix with pancreatic juices and enter the small intestine. Also, the absorptive cells release special enzymes. This allows for enzymatic digestion to take place in the small intestine. Mechanical digestion also takes place in the small intestine.
Segmentations take place, which are mixing contractions that churn and turn chyme. These contractions allow chyme to be mixed with gastric juices and bring the nutrients to the mucosa so they can then be absorbed. This keeps taking place until all the food in that area of the small intestine is digested.
Small Intestine Home of Many Bacteria Essential to Digestion
Your small intestine and large intestine are home to thousands of bacteria that live in symbiosis with you. Some of these bacteria are good for you because they help break down essential fats and nutrients, while others are not bad bacteria, when there are large numbers can make you sick. The trick is to always have a larger amount of good bacteria in your gut verus the bad bacteria.
The best way to do this is to give your good bacteria food it needs to survive. You see there are certain kinds of food which are perfect for them. This food for your bacteria is called prebiotic. Kiwi fruit, for example, is a great prebiotic, and functional food.