How does the pH of the contents of the gut vary from the stomach to the anus? I know that chyme is very acidic, but after that?
Not sure if I answered this right:
The system begins in the mouth, where the pH of saliva is 5.7 – 7.0. In the esophagus the pH is 7.0. The stomach pH is 1.5 – 3.0. In the Duodenum (upper part of the small intestine) pH is 4.0 – 5.0, and in the lower part of the small intestine (jejunum and ileum), pH 6.5 – 7.5
The reason for it:
In order to carry out their individual functions, each section of the digestive system maintains a pH that suits the needs of the environment. The first part of the system prepares the food for digestion. This section’s weak acidic surroundings begin the process. The second area, the stomach, must supply enough acid to break the food into its nutrients. However, when the food continues into the intestines, it no longer needs acid. Both intestines bring the matter closer to the pH of the body
Basically these values stay consistent with some minor changes, unless a person is experiencing a acid-base imbalance. These are life threatening and can be extremes in acid or alkaline. The pH as you can see stays within the range it needs to be, in order to process food.