Stomach acid in space?

Question

I guess you could call this a shower thought but out of the blue I thought about this. How does our stomach acids not float up our throats in zero G? I’m not familiar with how our bodies work in space and would love to hear an explanation

In: 12

Answer 1

The movement of stomach acids and other digestive fluids in the human body is primarily controlled by muscular contractions and valves rather than gravity. Therefore, even in zero gravity or microgravity environments, the digestive process can still occur effectively without the acids rising up.

In a normal gravity environment, such as on Earth, gravity helps in keeping the stomach acids and contents in the stomach by pulling them downward. The lower part of the esophagus, called the lower esophageal sphincter, acts as a valve that prevents the backward flow of stomach acids into the esophagus. This sphincter remains closed most of the time, except when we swallow food or liquid.

In zero gravity, the absence of gravitational force doesn’t affect the functioning of the esophageal sphincter or the muscular contractions responsible for moving food and digestive fluids through the digestive system. The rhythmic contractions, known as peristalsis, help push food downward through the esophagus and into the stomach. Similarly, the stomach muscles contract to mix the food with digestive enzymes and acids.

While some astronauts experience temporary effects like space sickness or changes in digestion during their initial adaptation to microgravity, the digestive process continues to function relatively normally. The body’s natural mechanisms, including the muscle movements and sphincter functions, work to keep the stomach acids in place and prevent them from rising up into the esophagus.

However, it’s worth noting that prolonged exposure to microgravity or space travel can have various effects on the human body, including changes in bone density, muscle mass, and other physiological functions. These changes are areas of active research for scientists studying the effects of space travel on human health.