The Small Intestine

Small Intestine

Our body has many organs that help us digest.   Some small, some big, and some that you don’t even notice is there.   Big or small with out them, we would all have trouble digesting.   People just don’t realize the value to our digestive system.   Of course they’re a lot of organs in your body, but I think one organ that really stands out is the small intestine.   Lets discuss the basics.
The small intestine is part of the gastrointestinal tract (gut) following the stomach and followed by the large intestine.   This is where the majority of digestion and absorption of food takes place. The small intestine in an adult human measures about 7 meters in length and is approximately 2.5-3 cm in diameter.   The really crazy thing about the small intestine is although the small intestine is much longer than the large intestine (typically 4-5 times longer), it gets its name from its relatively smaller diameter.  
The small intestine is divided into three structural parts:
  * Duodenum 26 cm (9.8 in) in length
  * Jejunum 2.5 m (8.2 ft)
  * Ileum 3.5 m (11.5 ft)
Now comes the digestive part of the small intestine.   Food from the stomach is allowed into the duodenum by a muscle in the stomach and is then pushed through the small intestine by a process of muscular-wavelike contractions called peristalsis.   The small intestine is where most chemical digestion takes place.   The three major classes of nutrients that encounter digestion are proteins, lipids (fats) and carbohydrates.
Now it’s time for the digested food to be absorbed.   The digested food can now pass into the blood vessels in the wall of the intestine.   The small intestine is the site where most of the nutrients from ingested food are absorbed. From the plicae circulares project microscopic, finger-like, pieces of tissue called villi (Latin for "shaggy hair"). The individual epithelial cells also have finger-like projections known as microvilli. The function of the plicae circulares, the...