How does human digestive system work in space?

By "space" I assume you mean free-fall or microgravity, the environment on space stations and in-flight spaceships. read more

The human digestive system does not depend on gravity to move food through it. Gravity helps, but is not essential to the movement of food through the gut. The human gut moves food by peristalsis. read more

Nope! Fortunately, our digestive tract is heavily muscled, so it actually contracts and squeezes to push food in the direction it needs to go, and we've got numerous valves that close off the various parts to prevent any backflow. read more

It dosen't in space and it dosen't on earth either. The food in your mouth is pushed to the stomach by muscles in the lining of the tube between mouth and your stomach. Then, in your stomach the digested food is pushed again into your intestines. read more