On a return visit after receiving a diagnosis of functional dyspepsia, a 35- year-old woman reports sensations of early satiety and discomfort in the epigastric region after a meal. These symptoms are most likely a result of:

Ans. A. Malfunction of adaptive relaxation in the gastric reservoirAs the gastric reservoir fills during a meal, mechanoreceptors signal the CNS. When the limits of adaptive relaxation in the reservoir are reached, signals from the stretch receptors in the reservoir's walls account for the sensations of fullness and satiety. Overdistension is perceived as discomfort. Adaptive relaxation appears to malfunction in the forms of functional dyspepsia characterized by the symptoms described in this question. If adaptive relaxation is compromised (e.g., by an enteric neuropathy), mechanoreceptors are activated at lower distending volumes and the CNS wrongly interprets the signals as if the gastric reservoir were full. None of the other choices would be expected to activate mechanosensory signaling of the state of fullness of the gastric reservoir.