Organ Histology of the Gallbladder

By: Masnoo Adem

The gallbladder is a pear-shaped organ that sits right under the liver. It is a small pouch that receives and stores the bile that the liver has produced. In humans, the gallbladder can store about 50 to 100 milliliters of bile. Bile is a yellow-green color and is used during the digestion of food. When you eat, the gallbladder is stimulated to contract, releasing the bile into the duodenum through the common bile duct. The duodenum is the upper part of the small intestine. In the duodenum, the bile is used to help break down the fat present in food. Though bile helps digest fats, the gallbladder isn’t absolutely necessary. It is very possible to live without one.

The inner surface of the gallbladder is covered by mucosa. The surface is made up of simple columnar epithelium. These epithelial cells have microvilli. Microvilli are small extensions of the cell membrane that increase surface area and assist in absorption and secretion functions. Underneath the epithelium, the lamina propria lays. The lamina propria is loose connective tissue that allows the epithelium to move freely and provides immune defense. The muscular layer of the gallbladder is made up of bundles of smooth muscle. Underneath this muscular layer is a thick layer of connective tissue that contains large blood vessels, nerves, and a lymphatic network. This connective tissue layer is located on the outside of the gallbladder. It’s known as the adventitia where it connects to the liver. The gallbladder does not contain a muscularis mucosa or submucosa. The muscularis mucosa is a thin layer of smooth muscle that provides support for the mucosa while allowing it to move and fold. The submucosa is a thick connective tissue layer that also supports the mucosa.

Reference links:

https://www.webmd.com/digestive-disorders/picture-of-the-gallbladder#1

https://www.histology.leeds.ac.uk/digestive/gallbladder.php

https://www.mayoclinic.org/diseases-conditions/gallstones/symptoms-causes/syc-20354214

https://www.mayoclinic.org/gallbladder-and-bile-duct/img-20008461

http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/micvil.html

http://www.pathologyoutlines.com/topic/gallbladderhistology.html

http://www.siumed.edu/~dking2/erg/giguide.htm

http://medcell.med.yale.edu/histology/gi_tract_lab.php