In some animals, including vertebrates, echinoderms, insects and molluscs, the stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract. It is involved in the second phase of digestion, following mastication. It secretes protein-digesting enzymes and strong acids to aid in food digestion through smooth muscular contortions before sending partially-digested food to the small intestines. Alternative Names: Stomach Lysate, Human Stomach Lysate, Human Stomach Tissue Lysate, Normal Human Stomach Lysate