Cheer for the Small Intestine

One rarely gives credit where credit is due when it comes to our marvelous digestion. After all, this is our fuel to power each and every cell, every moment, all day long.

Some digestion happens in the mouth, proteins and fats are digested mostly in the stomach, which also functions as a temporary reservoir. The rate of emptying the stomach will depend on the contents: a carbohydrate meal leaves the stomach in 2 to 3 hours, protein will remain a little longer and fatty meals remain the longest. These contents are called chyme when they leave the stomach for the duodenum, the top portion of the small intestines.

The pancreatic enzymes are excreted into the duodenum with a pH between 6 and 8, which brings the pH of the chyme to a level optimal for assimilation. The pancreatic secretions consist of water, mineral salts and a variety of enzymes. There are numerous enzymes each with specific functions to complete the digestive process of the variety of foods we consume each meal.

• Amylase converts starches to sugars
• Sucrase splits sugars into glucose and fructose
• Maltase acts upon malt sugars
• Lactase digests milk sugars
• Lipase converts fats to fatty acids and glycerol with the assistance of bile salts from the liver and gall bladder
• Peptidase converts peptides to amino acids
  

As the chyme enters the small intestine through the pyloric sphincter, it has begun a twisting, turning expedition of about 5 meters or 16 feet. It is almost like a carnival ride coiling through finger-like villi in slick tubes. They are under 1 cm in length and enclose in a network of blood and lymph capillaries. The walls of the villi consist of epithelial cells that absorb nutrients and, in some cases, complete the final stages of digestion. From here the nutrients are carried throughout the body in the blood.

What is left is a journey through the large intestine to decompose this stuff to “compost” material and elimination. Let’s give a big cheer for small intestine and it’s marvelous accomplishments.