The phrase "small intestine" refers to a part of our digestive system. It is a long, tube-like organ in our abdomen that helps break down and absorb the nutrients from the food we eat. Full definition
These mice also experienced twice the rate of cell death in small intestine. (mamanatural.com)
The indirect problem with this is that it causes inflammation which can stretch apart the cells of small intestine, eventually causing leaky gut. (mommypotamus.com)
In young puppies, most of those worms reach the animal's small intestine where they do severe damage. (2ndchance.info)