Describe how hormones regulate digestion.
Hormones control the different digestive enzymes that are secreted in the stomach and the intestine during the process of digestion and absorption. For example, the hormone gastrin stimulates stomach acid secretion in response to food intake. The hormone somatostatin stops the release of stomach acid.
Describe one or more scenarios where loss of hormonal regulation of digestion can lead to diseases.
There are many cases where loss of hormonal regulation can lead to illnesses. For example, the bilirubin produced by the breakdown of red blood cells is converted to bile by the liver. When there is malfunction of this process, there is excess bilirubin in the blood and bile levels are low. As a result, the body struggles with dealing with fatty food. This is why a patient suffering from jaundice is asked to eat a diet with almost zero fat.
A scientist is studying a model that has a mutation in the receptor for somatostatin that prevents hormone binding. How would this mutation affect the structure and function of the digestive system?
Somatostatin is the hormone that inhibits the release of HCl into the stomach lumen after the chyme has moved to the intestine. If the receptor for somatostatin is nonfunctional, somatostatin cannot signal to the stomach parietal cells to stop acid secretion. Thus, acid secretion will continue when there is no food present, and can cause damage to the stomach tissue. However, as long as the stomach remains intact the mutation should not slow digestion since acid will always be present in the stomach to digest any new boluses of food.