Question

In what organ does the majority of chemical digestion and absorption occur?

Answer 1

Majority of chemical digestion and absorption takes place in small intestine. It receives fat emulsifying bile from liver, digestive juice from pancraes, and secretes its own juice. It has villi to absorb digested nutrients.

Explanation:

In first part of small intestine, i.e. in duodenum, all digestive juices mix with half digested chyme. Bicarbonates of pancreatic juice nullifies the acidity of chyme provided by gastric juice. All digestive enzymes act in alkaline pH within small intestine.

There are no enzymes in bile but the bile salts act as emulsifies: large fat globules are broken down in microscopic spheres so that surface area increases, as a result lipase can act efficiently.

Protein digesting enzymes of pancreas (trypsinogen, chymotrypsinogen) are secreted in inactive form. Trypsinogen is activated by enterokinase enzyme present in intestinal juice into trypsin. Latter activates chymotrypsinogen.

To know about absorption, read the following:

https://socratic.org/questions/why-do-we-have-villi-in-the-small-intestine?source=search

https://socratic.org/questions/what-happens-in-the-small-intestine?source=search