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    From Digestive System

    Laryngopharynx
    Lower part of pharynx leading to esophagus.
    Neck of Pancreas
    Short section between head and body.
    Peritoneum
    Serous membrane lining the abdominal cavity.
    Pyloric Sphincter
    Regulates passage of chyme from stomach to duodenum.
    Round Ligament of Liver
    Remnant of fetal umbilical vein.
    Ascending Colon
    Vertical segment of the colon on the right side.
    Uvula
    Dangling soft tissue at the back of the soft palate.
    Descending Colon
    Vertical segment of the colon on the left side.
    Mesocolon
    Peritoneal fold attaching colon to posterior wall.
    Left Lobe
    Smaller lobe of the liver.
    Ileum
    Final and longest portion of the small intestine.
    Minor Duodenal Papilla
    Opening for accessory pancreatic duct.
    External Anal Sphincter
    Voluntary muscle around anus.
    Internal Anal Sphincter
    Involuntary muscle around anal canal.
    Oropharynx
    Middle region of the pharynx behind the oral cavity.
    Sigmoid Colon
    S-shaped final segment of the colon.
    Cystic Duct
    Connects gallbladder to common bile duct.
    Ileocecal Valve
    Controls flow from ileum to cecum.
    Abdomen
    The abdomen is the body region between the chest and pelvis housing vital digestive, metabolic, and excretory organs, protected by muscular and peritoneal layers.
    Oral Cavity
    Entry point of the digestive system; includes teeth, tongue, and salivary openings.
    Major Duodenal Papilla
    Opening for bile and pancreatic ducts into duodenum.
    Lesser Omentum
    Connects stomach and liver.
    Caudate Lobe
    Lobe of liver near inferior vena cava.
    Common Hepatic Duct
    Carries bile from liver to bile duct.
    Palatine Tonsils
    Lymphatic tissues on either side of the oropharynx.

    Haustra

    Reviewed by our medical team

    Pouch-like segments of colon.

    Overview

    Haustra are small, pouch-like sacculations or bulges along the wall of the large intestine. They give the colon its segmented appearance and play an important role in segmental mixing and movement of fecal matter. Haustra are a distinctive anatomical feature of the colon and are created by the action of specialized longitudinal muscle bands known as the taeniae coli.

    Location

    Haustra are found throughout the entire colon, specifically:

    • Beginning at the cecum and extending through the ascending, transverse, descending, and sigmoid colon

    • Not present in the rectum or vermiform appendix

    They are visible externally as bulges between the taeniae coli and appear internally as crescent-shaped folds called semilunar folds.

    Structure

    Each haustrum is formed by:

    • Localized contractions of the taeniae coli: Three distinct longitudinal muscle bands that are shorter than the length of the colon, causing the colon to pucker

    • Circular muscle layer: Contracts intermittently to define the haustral borders

    • Internal mucosal folds: Known as plicae semilunares, they correspond to the external haustra and segment the colon internally

    Haustra are not permanent structures; they shift in response to intraluminal contents and motility patterns.

    Function

    Haustra perform several critical functions in the colon:

    • Segmental mixing: Facilitate the mixing of colonic contents to enhance water and electrolyte absorption

    • Slow transit: Regulate the pace of fecal movement, allowing sufficient time for fluid reabsorption

    • Storage: Temporarily hold fecal matter within each haustrum before advancing to the next

    Physiological Role(s)

    In terms of gastrointestinal physiology, haustra contribute to:

    • Colonic motility: Haustral contractions are a type of segmental motility that differ from peristalsis and occur independently in different segments

    • Fluid balance: Aid in the extraction of water and salts from feces by prolonging contact with the mucosa

    • Bacterial fermentation: Prolonged mixing allows gut flora to metabolize undigested carbohydrates, generating short-chain fatty acids and gases

    Clinical Significance

    Haustra are important in the diagnosis and pathology of various intestinal conditions:

    • Loss of haustration: A smooth, featureless colon (often called a lead pipe colon) is characteristic of chronic ulcerative colitis

    • Haustral thickening: Can be seen in conditions like ischemic colitis, infectious colitis, or diverticulitis

    • Toxic megacolon: Haustra may disappear in this life-threatening complication of severe colitis, indicating dilatation and muscle paralysis

    • Radiographic significance: Haustra are visible on contrast studies and CT scans, helping distinguish the colon from small intestine (which has valvulae conniventes)

    Understanding the normal appearance and function of haustra is essential for interpreting abdominal imaging and diagnosing large bowel pathology.

    Did you know? The stomach can expand to hold up to 4 liters of food or liquid.