I gather the digestive system extracts the nutrients from the food and moves them around in the body to nourish all the cells. What gets nourished first, perhaps the digestive system itself? And next, and next, and so on? I suppose the question might be whether the blood carrying the nutrients nourishes the digestive system itself, and where it travels and in what order it reaches different places.
Wow, this comment is really splitting hairs. It takes about a minute for the blood to circulate throughout the entire body. The blood carries nutrients. Everything gets nutrients at the same time (+ or - 1 minute of course).