Hormone which brings about the contraction of gall bladder is

Options

A. Oxygocin
B. Gastrin
C. Cholecystokinin
D. Secretin

Answer

To determine which hormone brings about the contraction of the gallbladder, we can analyze the options provided: oxytocin, gastrin, cholecystokinin, and secretin.

1. **Understanding the Role of Each Hormone:**
- **Oxytocin:** This hormone is produced in the pituitary gland and primarily stimulates contractions in the uterus during childbirth and helps with milk ejection. It does not play a role in gallbladder contraction.
- **Gastrin:** This hormone is secreted by G-cells in the stomach and is responsible for stimulating the secretion of gastric acid. It is involved in the digestive process but does not directly cause gallbladder contraction.
- **Cholecystokinin (CCK):** This is a peptide hormone released from the gastrointestinal tract, particularly in response to the presence of fats in the small intestine. CCK is known to stimulate the contraction of the gallbladder, leading to the release of bile, which is essential for the emulsification and digestion of fats.
- **Secretin:** This hormone is also released from the gastrointestinal tract and primarily stimulates the secretion of bicarbonate from the pancreas and bile from the liver. However, it does not directly cause gallbladder contraction.

2. **Conclusion:**
Based on the functions of these hormones, the hormone responsible for the contraction of the gallbladder is **Cholecystokinin (CCK)**.

### Final Answer:
The hormone which brings about the contraction of the gallbladder is **Cholecystokinin (CCK)**.