Your stomach. The internal organ in which the major part of the digestion of food occurs, being, in humans and many mammals, a pear-shaped enlargement of the alimentary canal linking the esophagus to the small intestine. Let's compare the human stomach to cellular organelles. Which organelle is involved in cellular digestion and contains digestive enzymes? A) vacuole B) lysosome C) ribosome D) Golgi body