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| Hormonal Control of Digestion |
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| Digestion is also controlled by the secretion of organic substances called hormones by the endocrine glands. Each hormone has a specific target organ. The hormones reach the target organ through the blood stream. The hormones controlling digestion are secreted by the walls of the stomach and duodenum. The hormones controlling digestion are: |
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| Gastrin |
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| The stretching of the stomach wall and the presence of food in the stomach stimulates the production of gastrin by the gastric mucosa. The target organs of gastrin are the gastric glands which are stimulated to produce gastric juice and also secretion of HCl. |
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| Cholecystokinin (CCK) |
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| The duodenal mucosa secretes CCK in response to the presence of partially digested fats and proteins present in the chyme. The functions of CCK is to inhibit emptying of stomach, synthesis of digestive enzymes by pancreas and contraction of gall bladder. Thus the target organs are stomach, pancreas and gall bladder. |
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| Secretin |
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| Secretin is also secreted by the duodenal mucosa, in response to the presence of acidified chyme in the duodenum. The functions of secretin are to inhibit the production of gastric juice and stimulate the production of hydrogencarbonate ions in the pancreatic and bile juice. Thus the target organs of secretin are stomach, pancreas and liver respectively. |
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