Motilin is secreted by cells in:

Appeared in: AIIMS Nagpur NO- 2020

Explanation

Motilin is a peptide hormone secreted by enterochromaffin cells and Mo cells, which are located in the mucosa of the small intestine.
While the highest concentration of secretion occurs in the upper small intestine (duodenum and jejunum), these cells are also found in the ileum, making it a correct site of secretion among the given options.
The primary function of motilin is to initiate the Migrating Motor Complex (MMC), which are strong peristaltic waves that occur during fasting to cleanse the gut.

Option A: The liver's main functions are metabolic and secretory (bile production), not hormonal secretion of motilin.
Option B: The esophagus is a muscular conduit for food and does not have a significant role in hormone secretion.
Option C: The pancreas is a major endocrine and exocrine gland but does not secrete motilin. Its key hormones are insulin and glucagon.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of gastrointestinal motility as background academic context rather than a clinical decision trigger.
Some antibiotics, like erythromycin, are motilin receptor agonists. They are sometimes used off-label as prokinetic agents to stimulate gut motility in patients with conditions like gastroparesis (delayed gastric emptying).
A functional understanding of motilin helps the nurse anticipate potential side effects of erythromycin, such as abdominal cramping and diarrhea, which are caused by its prokinetic action.
What if? If a patient has chronically low levels of motilin during fasting, they might experience symptoms like bloating, nausea, and early satiety. This is because the 'housekeeping' function of the Migrating Motor Complex would be impaired, leading to delayed gastric emptying.

How to Approach the Question

First, identify the core subject of the question, which is the origin of the hormone 'motilin'.
This is a factual recall question from physiology. Access your knowledge about the endocrine functions of the gastrointestinal tract.
Systematically evaluate each option. Recall the primary functions of the liver (metabolism, bile), esophagus (peristalsis), and pancreas (digestive enzymes, insulin/glucagon).
These functions do not include motilin secretion, which allows you to eliminate options A, B, and C.
Recall that motilin is a GI hormone involved in motility. The ileum is part of the small intestine, a major site for GI hormone production. This makes it the most plausible answer among the choices.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 2A p. 168-170

E6 Physiology Ganong 27e Vol 2 Part 1 p. 15-17

Practise the full AIIMS Nagpur NO- 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.