Name of the duodenal hormone is?

ESIC Nursing Officer 2016 (shift-1)

Applied Physiology

Easy

Appeared in: ESIC Nursing Officer 2016 (shift-1)

Explanation

Cholecystokinin (CCK) is a key hormone secreted by I-cells in the mucosa of the duodenum and jejunum.
Its release is stimulated by the presence of fats and amino acids in the chyme arriving from the stomach.
The primary functions of CCK are to stimulate the contraction of the gallbladder to release bile and to trigger the pancreas to secrete digestive enzymes.
CCK also slows gastric emptying and acts as a satiety signal to the brain.

Option A: While Motilin is secreted by the duodenum, its primary function is to stimulate the migrating motor complex (MMC), which are waves of motility that clean the gut during fasting periods. It is not the primary hormone involved in the digestive response to a meal.
Option B: Acid pepsin is not a hormone. It refers to the combination of hydrochloric acid and the enzyme pepsin, which are components of gastric juice in the stomach responsible for protein digestion.
Option D: Gastric Inhibiting Peptide (GIP), now more accurately called glucose-dependent insulinotropic polypeptide, is a duodenal hormone. However, its principal physiological role is to act as an incretin, stimulating insulin release in response to glucose. Its effect on gastric inhibition is less significant than its insulinotropic effect.

Visual 1: Diagram: An illustration of the upper gastrointestinal tract showing the stomach, duodenum, pancreas, and gallbladder. Arrows should indicate that chyme in the duodenum stimulates CCK release, which then acts on the gallbladder (causing contraction) and the pancreas (causing enzyme secretion).
Visual 2: Flowchart: A flowchart detailing the hormonal regulation of digestion. It would start with 'Food (fats, proteins) enters duodenum', leading to 'I-cells release CCK', which then branches to 'Gallbladder contracts' and 'Pancreas secretes enzymes'.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Function of Duodenal Hormones as background academic context rather than a clinical decision trigger.
A synthetic form of CCK (sincalide) is used during a HIDA scan (hepatobiliary iminodiacetic acid scan) to evaluate gallbladder function. The test measures the gallbladder ejection fraction after CCK stimulation, which helps diagnose conditions like chronic cholecystitis or biliary dyskinesia.
Understanding CCK's role is crucial in managing patients with pancreatitis or gallstones, as the hormone's activity directly influences these organs.
What if? If a patient has a condition that blocks the bile duct (e.g., a gallstone), the CCK-stimulated contraction of the gallbladder would cause a sharp increase in pressure, leading to severe biliary colic pain.

How to Approach the Question

First, identify the key term in the question: 'duodenal hormone'. This directs you to focus on hormones originating from the first part of the small intestine.
Next, evaluate each option. Ask yourself: 'Is this a hormone?' and 'Is it secreted by the duodenum?'.
Immediately eliminate 'Acid pepsin' as it is a combination of an acid and an enzyme, not a hormone.
You are left with three hormones: Motilin, Cholecystokinin, and Gastric Inhibiting Peptide. All are secreted by the duodenum.
To find the best answer, recall the primary function of each. Motilin is for fasting motility, GIP is mainly for insulin release, and CCK is central to the immediate digestion of fats and proteins. CCK is the most direct and significant answer for a general question about duodenal digestive hormones.

Concept Tested & Keywords

QiwAFaj-aoWFYQ8e_8iWlS