The outermost layer of the gallbladder wall is which of the following?

• A. Outer serosal layer
• B. Subserosal
• C. Muscular layer
• D. Inner epithelial layer

Answer: (A)

The main idea here is the layering of the gallbladder wall. Because the gallbladder is intraperitoneal, its outer surface is covered by a serous membrane called the serosa, which is the visceral peritoneum. This serosal layer is the outermost covering and provides a smooth, friction-reducing surface as the gallbladder moves with digestion. Inside, you have the muscular layer made of smooth muscle that helps concentrate and release bile, and deepest to the lumen is the mucosal lining of tall columnar epithelium. The term subserosal isn’t a distinct functional layer in this context, and the inner epithelial layer sits farthest inside. So the outermost layer is the serosa.