The enterogastric reflex stimulates stomach emptying is false why?
Reading File
Finding Sources
Reading File
Reading File
The textbook sources confirm the answer clearly. Here is the full explanation:
Why "Enterogastric Reflex Stimulates Stomach Emptying" is FALSE
The statement is false because the enterogastric reflex inhibits (slows down) stomach emptying - it is a negative feedback / braking reflex, not a stimulatory one.
What the Enterogastric Reflex Actually Does
When chyme enters the duodenum and small intestine, sensory signals are triggered that travel back to the stomach to reduce its motor activity and secretion. This is a protective mechanism - the small intestine signals the stomach to slow down so it does not get overwhelmed.
Triggers for the Reflex
The reflex is initiated by the following stimuli in the upper small intestine:
| Stimulus | Purpose |
|---|---|
| Distension of the small bowel | Too much volume already present |
| Acid in the duodenum | Protects mucosa from acid damage |
| Protein breakdown products | Signals active digestion already underway |
| Hyperosmotic or hypo-osmotic fluids | Prevents osmotic stress |
| Irritation of the mucosa | Protective mechanism |
Pathway
The reflex is transmitted through:
- The myenteric nervous system (intrinsic/enteric)
- Extrinsic sympathetic nerves (via prevertebral ganglia - notably, sympathetic activity inhibits GI motility)
- Vagus nerves
As stated directly in Guyton & Hall: signals travel "from the colon and small intestine to inhibit stomach motility and stomach secretion (the enterogastric reflexes)."
Why the Confusion Might Arise
The name "enterogastric" could mislead someone to think it activates the stomach. In reality, "enterogastric" simply describes the direction of the signal (intestine → stomach), not the nature of the effect. The effect is always inhibitory.
Summary
- Enterogastric reflex = intestine signals stomach to SLOW DOWN
- It reduces both gastric motility and secretion
- It is a key mechanism preventing the small intestine from being flooded with undigested chyme
"The enterogastric inhibitory reflexes plus inhibitory hormones usually also reduce stomach motility at the same time that they reduce gastric acid secretion."
- Guyton and Hall Textbook of Medical Physiology
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