how does the food reaches to the small intestine when we sleep at night just after having dinner, which is against the gravity as the food has to go parallel to the earth surface?
In: Biology
Our bodies don’t use gravity to move food. The digestive tract is covered in muscles, and has muscular seals (called sphincters) at certain points where backwards flow is considered particularly bad.
The stomach has two sphincters – one at the top, to let new food in; and one at the bottom, to let old food out into the small intestine.
When you swallow new food, the stomach relaxes and the top sphincter opens to let it in. Meanwhile, the food is pushed in by the muscles of the esophagus.
Now, when the stomach is done digesting that food, it keeps the top sphincter closed, opens the bottom sphincter, and pushes the food into the small intestine.
Once there, the walls of the small intestine contract in waves, moving from its entrance to its exit, to move the food along without relying on gravity.
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