Which cells in the stomach are involved in the initial phase of chemical digestion?

The cells in the stomach that are primarily involved in the initial phase of chemical digestion are the chief cells. These cells are responsible for producing pepsinogen, an inactive enzyme that is converted into pepsin when it comes into contact with the acidic environment of the stomach. Pepsin plays a crucial role in breaking down proteins into smaller peptides, which is a key part of the digestive process.

While parietal cells are important for producing gastric acid, which creates the acidic environment necessary for pepsin activation, and neck cells contribute to mucus production for protection, it is the chief cells that directly initiate the breakdown of proteins through the secretion of digestive enzymes. Endocrine cells in the stomach primarily produce hormones that regulate digestion but do not directly participate in the chemical digestion of food. Thus, the role of chief cells in secreting pepsinogen makes them central to the initial phase of chemical digestion in the stomach.