Final answer:
During stress, the stomach's increased compound is hydrochloric acid (HCl), which is stimulated by the hormone gastrin. The secretion of HCl aids digestion but is balanced by stomach mechanisms to prevent harm from excessive acid.
Step-by-step explanation:
During times of stress, the compound increased in the stomach is hydrochloric acid (HCl). This increase is stimulated by gastrin, a hormone released from enteroendocrine G cells in response to partially digested proteins, caffeine, and a rising pH level. Gastrin triggers parietal cells in the stomach lining to secrete more HCl. In a stressful situation, various physiological changes occur, including the secretion of digestive juices in anticipation of food, the activation of the fight-or-flight response facilitated by the sympathetic nervous system, and the release of stress hormones like cortisol by the hypothalamic-pituitary-adrenal (HPA) axis, which can broadly affect numerous organs. To maintain a balance and prevent excessive acid secretion, the stomach has mechanisms like suspending HCl secretion and increasing mucus secretions when pH levels drop too low.