Logo

    Related Topics

    From Digestive System

    Stomach
    Muscular sac that begins digestion of protein.
    Vermiform Appendix
    Worm-like appendage of the cecum.
    Submandibular Glands
    Salivary glands beneath the mandible.
    Accessory Pancreatic Duct
    Secondary duct emptying into duodenum.
    Cystic Duct
    Connects gallbladder to common bile duct.
    Cheeks
    Lateral walls of the oral cavity composed of muscle and fat.
    Ascending Colon
    Vertical segment of the colon on the right side.
    Falciform Ligament
    Connects liver to anterior abdominal wall.
    Sigmoid Colon
    S-shaped final segment of the colon.
    Descending Colon
    Vertical segment of the colon on the left side.
    Round Ligament of Liver
    Remnant of fetal umbilical vein.
    Anus
    Opening through which feces are expelled.
    Pyloric Sphincter
    Regulates passage of chyme from stomach to duodenum.
    Lower Esophageal Sphincter
    Muscle at the junction of esophagus and stomach.
    Pylorus
    Distal part of stomach leading to duodenum.
    Neck of Pancreas
    Short section between head and body.
    Gingiva
    Gums; soft tissue covering the bones of the jaw.
    Sublingual Glands
    Salivary glands beneath the tongue.
    Upper Esophageal Sphincter
    Muscle ring that controls entry into the esophagus.
    Esophagus
    Muscular tube conveying food from the pharynx to the stomach.
    Duodenal Bulb
    Initial section of duodenum closest to the stomach.
    Quadrate Lobe
    Small lobe located between gallbladder and round ligament.
    Cecum
    First part of large intestine.
    Jejunum
    Second portion of the small intestine.
    Left Lobe
    Smaller lobe of the liver.

    Mesentery

    Reviewed by our medical team

    Fold of peritoneum anchoring intestines.

    Overview

    The mesentery is a continuous fold of double-layered peritoneum that attaches portions of the intestine to the posterior abdominal wall. It acts as a supportive and suspensory structure while serving as a conduit for blood vessels, lymphatics, and nerves. Once considered a fragmented structure, recent anatomical understanding classifies the mesentery as a single, continuous organ that plays vital roles in digestion, immunity, and structural integrity of the gut.

    Location

    The mesentery is located in the abdominal cavity and is classified based on the portion of the gastrointestinal tract it supports:

    • The mesentery proper: Connects the jejunum and ileum to the posterior abdominal wall

    • Mesocolon: Includes the transverse mesocolon, sigmoid mesocolon, and mesoappendix

    • Mesorectum: Attaches the rectum to the sacrum and posterior pelvic wall

    • Other mesenteries: Include the mesogastrium (stomach) and mesoduodenum (first parts of duodenum)

    All mesenteric structures arise from the dorsal mesentery during embryological development, except the ventral mesentery of the foregut.

    Structure

    The mesentery consists of:

    • Two layers of peritoneum: Enclosing connective tissue and a loose fatty matrix

    • Blood vessels: Including branches of the superior mesenteric artery and vein for the small intestine

    • Lymphatic vessels: Important for fat absorption and immune cell trafficking

    • Nerves: Derived from the autonomic plexuses to innervate the intestines

    • Lymph nodes: Embedded within the mesentery for gut-associated immune response

    The mesentery has a root approximately 15 cm long, obliquely oriented from the left upper quadrant (L2) to the right lower quadrant (sacroiliac region).

    Function

    The mesentery serves several essential functions:

    • Suspends the intestine: Anchors the intestines while allowing mobility for peristalsis and digestion

    • Supports neurovascular supply: Conveys arteries, veins, lymphatics, and nerves to the intestines

    • Maintains gut alignment: Prevents intestinal twisting or volvulus

    • Pathway for immune cells: Houses lymph nodes and immune cells involved in gut immunity

    Physiological Role(s)

    The mesentery contributes to overall digestive physiology through:

    • Absorption of nutrients: Transports absorbed nutrients, including fats via lacteals, from the intestines to the bloodstream

    • Fat storage: The mesentery contains adipose tissue that serves as an energy reserve and insulator

    • Immune surveillance: Lymph nodes filter antigens and coordinate immune responses to pathogens in the gut

    • Inflammatory signaling: Plays a role in local inflammatory responses, particularly in diseases like Crohn's

    Clinical Significance

    The mesentery is involved in various pathological and surgical conditions:

    • Mesenteric ischemia: Occlusion of mesenteric arteries can lead to intestinal infarction, a surgical emergency

    • Mesenteric lymphadenitis: Enlargement of mesenteric lymph nodes, often due to viral or bacterial infection

    • Mesenteric tumors: Includes rare neoplasms like mesenteric fibromatosis or liposarcoma

    • Inflammatory bowel disease: In Crohn's disease, mesenteric fat wrapping ("creeping fat") is a hallmark feature

    • Internal hernias: May involve mesenteric defects allowing bowel loops to protrude and cause obstruction

    • Mesenteric traction syndrome: A perioperative complication characterized by hypotension due to mesenteric manipulation

    • Surgical access and resection: Surgeons rely on the mesentery for vascular control in resections, transplants, or anastomoses

    Recent reclassification of the mesentery as a continuous organ has implications for surgery, imaging, embryology, and disease understanding. CT and MRI imaging are frequently used to assess mesenteric pathology.

    Did you know? The small intestine absorbs more than 90% of the nutrients from food.