How does the circulatory system interact with the digestive system ?

The digestive system breaks down food molecules into their component parts, which are then absorbed by the circulatory system in the small intestine and circulated throughout the body. The digestive system diffuses nutrients into the capillaries and then through the circulatory system. The small intestine has folds called villi, and the villi contain tiny projections called microvilli. The microvilli absorb nutrients from digested food and transport it directly into the bloodstream where it can be used. Without the circulatory system, the body would not be able to absorb nutrients from the food we eat.

The circulatory system supplies the organs with blood and oxygen to keep them alive. Oxygen travels throughout the body including the digestive system. Like any organ, the digestive system requires more oxygen when metabolically active, for example after a meal. In addition, the digestive system plays a role in the acid-base balance in the body. Since H+ + HC03- exchanges with H20 and C02 within the intestine there is a production of carbon dioxide from the gut to the lungs.

The bloodstream carries nutrients that are broken by the digestive system from the food you eat. The circulatory system provides nutrients and oxygen to the organs of the digestive system.

Nutrients taken in and broken down by the digestive system are carried to various parts of the body by the circulatory system.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.