Unformatted text preview: substances between cells (of the food). The HCl also kills most bacteria that may accompany the food. • Chemical breakdown. Proteins are chemically broken down by the enzyme pepsin. Chief cells, as well as other stomach cells, are protected from self-digestion because chief cells produce and secrete an inactive form of pepsin, pepsinogen. Pepsinogen is converted to pepsin by the HCl produced by the parietal cells. Only after pepsinogen is secreted into the stomach cavity can protein digestion begin. Once protein digestion begins, the stomach is protected by the layer of mucus secreted by the mucous cells. • Controlled release. Movement of chyme into the small intestine is regulated by a sphincter at the end of the stomach, the pyloric sphincter....
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- Spring '10
- gastric juice, stomach cells, pepsinogen. Pepsinogen, four liters, Mixing. The stomach