Maximum contraction of gall bladder is seen with
**Core Concept**
The **gallbladder** plays a crucial role in the digestion of fats by storing and concentrating **bile**, which is produced by the **liver**. The contraction of the gallbladder is essential for releasing bile into the **biliary tree** and ultimately into the **duodenum**, where it aids in fat emulsification. This process is regulated by various **hormones** and **neurotransmitters**.
**Why the Correct Answer is Right**
The maximum contraction of the gallbladder is seen with **cholecystokinin (CCK)**, a **hormone** released by the **duodenum** in response to the presence of **fatty acids** and **amino acids**. CCK stimulates the **gallbladder** to contract, releasing **bile** into the **biliary tree**. This mechanism is crucial for efficient **fat digestion** and **absorption**.
**Why Each Wrong Option is Incorrect**
**Option A:** Is incorrect because while **acetylcholine** does stimulate gallbladder contraction, it is not the most potent stimulus.
**Option B:** Is incorrect because **secretin** primarily stimulates **bicarbonate** secretion from the **pancreas** and **biliary tree**, but does not cause significant gallbladder contraction.
**Option D:** Is incorrect because **gastrin** mainly stimulates **gastric acid** secretion and has a minimal effect on gallbladder contraction.
**Clinical Pearl / High-Yield Fact**
Remember, **cholecystokinin (CCK)** is the key hormone regulating gallbladder contraction and **pancreatic enzyme** secretion, making it a high-yield fact for exams.
**Correct Answer:** D. Cholecystokinin