Final answer:
The local gastrointestinal reflex that prepares the small intestine for the introduction of chyme is the d) gastroileal reflex. This reflex increases the strength of segmentation in the ileum and is controlled by both nerves and hormones like gastrin.
Step-by-step explanation:
The gastrointestinal (GI) reflex that prepares the small intestine for the introduction of chyme is the gastroileal reflex. This reflex is a long reflex that increases the strength of segmentation in the ileum, thus preparing the small intestine for the incoming chyme. There are several important aspects of GI reflexes to consider:
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- Short reflexes are provoked by nerves near the GI tract and are mediated by the enteric nervous system.
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- Food that distends the stomach can initiate long reflexes.
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- The presence of food in the stomach can activate the gastrocolic reflex, leading to propulsive movements in the colon.
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- The gastroileal reflex, specifically, increases ileal motility and relaxes the ileocecal sphincter, which is controlled by both nerves and hormones like gastrin.
Backward pressure after chyme passes through helps in closing the sphincter and preventing backflow into the ileum. The activity of the gastric pit, release of gastrin, and the three phases of gastric control (cephalic, gastric, and intestinal) contribute to the intricate processes of digestion. The gastroileal reflex ensures that the digestive tract is prepared and motivated for efficient digestion and passage of food.
In conclusion, the correct answer to the question about which local GI reflex prepares the small intestine for the introduction of chyme is d) Gastroileal reflex.