Understanding the Mesentery
The mesentery is a double layer of peritoneum, a thin membrane that lines the abdominal cavity. It essentially acts like a "suspension bridge," holding the intestines in place and providing them with blood supply, lymph drainage, and nerves.
What to Look for
1. Location: The mesentery is located within the abdominal cavity, specifically connecting the small intestine to the dorsal body wall.
2. Appearance:
* Shiny: The mesentery has a thin, translucent appearance, often described as shiny or iridescent.
* Vascular: You'll see numerous blood vessels (arteries and veins) branching throughout the mesentery, giving it a web-like or lacey pattern.
* Delicate: The mesentery is quite delicate and easily torn, so handle it with care.
3. Structure:
* Double-layered: It consists of two layers of peritoneum fused together, with a space between them containing blood vessels, nerves, and fat.
* Attached to intestine: The mesentery is attached to the small intestine along its entire length, forming a fan-like structure.
* Attachment to body wall: The other end of the mesentery is attached to the dorsal body wall, anchoring the intestines in place.
Dissecting Tips:
* Carefully remove the intestines: When you're dissecting the fetal pig, be gentle when removing the intestines to avoid damaging the mesentery.
* Identify the small intestine: Focus on the section of the digestive tract that's long, coiled, and narrower - this is the small intestine.
* Look for the "fan" structure: The mesentery will be evident as a thin, transparent, and highly vascularized structure extending from the small intestine towards the dorsal body wall.
Important Note: It's crucial to follow proper safety procedures and guidelines when dissecting a fetal pig. If you're unsure about any aspect of the dissection, seek guidance from your teacher or lab instructor.