When referring to the lumen of the stomach is that just the opening. As in where are the HCl is and where your food enters? I googled the definition of lumen and it says inside space. I'm just not too clear on what it really means. Thanks.

Answer 1

Try more specific key words, like "lumen of the stomach."

http://www.google.com/search?client=safari&rls=en&q=lumen+of+the+stomach&ie=UTF-8&oe=UTF-8