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The small intestine is a long, highly convoluted tube in the digestive system that absorbs about 90% of the nutrients from the food we eat. It is given the name âsmall intestineâ because it is only 1 inch in diameter, making it less than half the diameter of the large intestine.
In our last issue, we explored the physiology of digestion in the small intestine and started our discussion of nutrient absorption. In this issue, we conclude that discussion. Effectively, this is the heart and soul of our entire series on the digestive tract. Ultimately, everything that happens in the digestive tract is designed to get nutrients into the bloodstream. The final step in the process, absorption, is in many ways the most fascinating part of the discussion. Stomach acid unwinding proteins and pepsin breaking them down -- that's simple stuff.