Connection lost. Please refresh the page.
Get help How to study Login Register
Ready to learn?
Pick your favorite study tool


Recommended video: Peritoneal relations [27:50]
Peritoneal cavity as seen in a parasagittal section.

The serosa, also known as the serous membrane, is a single layer of simple squamous epithelium called mesothelium. It is supported by a thin underlying layer of loose connective tissue, abundant in blood vessels, lymphatic vessels, nerves and adipose tissue. It lines closed body cavities including the pericardial, peritoneal and pleural cavities and forms the outermost covering of organs within these cavities.

The serosa consists of two parts: a parietal layer that lines the body cavity and a visceral layer that envelops the organs. It secretes a thin, watery transudate called serous fluid, which reduces friction between the contacting surfaces of the parietal and visceral layers. In addition to reducing friction, the serosa serves as a protective barrier and provides structural support to certain organs, helping to anchor them in place.

In the peritoneal cavity, the serosa forms the outermost layer of the gastrointestinal (GI) tract wall, which is continuous with the mesothelium of the mesenteries and the peritoneum. In regions where the GI tract lacks a serosal layer, such as the thoracic part of the esophagus, and in certain retroperitoneal organs including the duodenum, ascending and descending colon, as well as in extraperitoneal organs like the rectum and anal canal, a thick connective tissue layer known as the adventitia blends with the tissues of neighboring structures.

Terminology English: Serosa
Synonyms: Serous membrane, serous coat

Tunica serosa
Definition Thin layer of connective tissue that lines certain internal body cavities and envelops the organs within these cavities.
Function - Protective outer layer for internal organs
- Reduces friction between organs and surrounding structures
- Supports organ attachment to body walls

Learn more about the serosa, with a focus on the peritoneal cavity in the following study unit:

Serosa: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

“I would honestly say that Kenhub cut my study time in half.” – Read more.

Kim Bengochea Kim Bengochea, Regis University, Denver
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Register now and grab your free ultimate anatomy study guide!