process of Digestion and Absorption of small intestine

The small intestine is where the majority of food digestion occurs. At this point carbohydrates and proteins are already partially digested, while lipids have not yet begun. Chyme leaves the stomach and enters the duodenum (the 1st portion of the small intestine) via the pyloric sphincter. Here, maltase breaks down maltose into glucose monomers and peptidases break down peptides into amino acids. Bile is then released from the gall bladder and enters the small intestine via the bile duct to aid in the digestion of fats into glycerol and fatty acids. The chyme then enters the jejunum (the 2nd portion of the small intestine) where digestion continues and absorption begins(the jejunum is composed of many fold that increase its surface area and therefore improve absorption.) Glucose and amino acids are transported across the membrane by means of active transport (requires ATP) while glycerol and fatty acids require the help of carrier proteins (micelles (produced in the liver)) to enter the blood stream. Next, the chyme enters the ileum (the 3rd portion of the small intestine) which is mainly responsible for the absorption of select nutrients (ie. vitamin c). Once the chyme leaves the small intestine, most of the nutrients have been absorbed and only waste products and water remain; this is called liquid stool.

The small intestine is where the majority of food digestion occurs. At this point carbohydrates and proteins are already partially digested, while lipids have not yet begun. Chyme leaves the stomach and enters the duodenum (the 1st portion of the small intestine) via the pyloric sphincter. Here, maltase breaks down maltose into glucose monomers and peptidases break down peptides into amino acids. Bile is then released from the gall bladder and enters the small intestine via the bile duct to aid in the digestion of fats into glycerol and fatty acids. The chyme then enters the jejunum (the 2nd portion of the small intestine) where digestion continues and absorption begins(the jejunum is composed of many fold that increase its surface area and therefore improve absorption.) Glucose and amino acids are transported across the membrane by means of active transport (requires ATP) while glycerol and fatty acids require the help of carrier proteins (micelles (produced in the liver)) to enter the blood stream. Next, the chyme enters the ileum (the 3rd portion of the small intestine) which is mainly responsible for the absorption of select nutrients (ie. vitamin c). Once the chyme leaves the small intestine, most of the nutrients have been absorbed and only waste products and water remain; this is called liquid stool.