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    Related Topics

    From Digestive System

    Main Pancreatic Duct
    Primary duct draining pancreatic juices.
    Teniae Coli
    Longitudinal muscle bands of colon.
    Parotid Glands
    Largest salivary glands located near the ear.
    Vermiform Appendix
    Worm-like appendage of the cecum.
    Right Lobe
    Larger functional lobe of the liver.
    Left Lobe
    Smaller lobe of the liver.
    Peritoneum
    Serous membrane lining the abdominal cavity.
    Major Duodenal Papilla
    Opening for bile and pancreatic ducts into duodenum.
    Soft Palate
    Muscular posterior part of the roof of the mouth.
    Haustra
    Pouch-like segments of colon.
    External Anal Sphincter
    Voluntary muscle around anus.
    Pyloric Sphincter
    Regulates passage of chyme from stomach to duodenum.
    Pylorus
    Distal part of stomach leading to duodenum.
    Cystic Duct
    Connects gallbladder to common bile duct.
    Quadrate Lobe
    Small lobe located between gallbladder and round ligament.
    Liver
    Largest gland in the body with roles in metabolism and bile production.
    Esophagus
    Muscular tube conveying food from the pharynx to the stomach.
    Common Hepatic Duct
    Carries bile from liver to bile duct.
    Abdominal Cavity
    The abdominal cavity is the largest body cavity, housing vital digestive and excretory organs, lined by the peritoneum and essential for protection, metabolism, and organ movement.
    Uvula
    Dangling soft tissue at the back of the soft palate.
    Fundus
    Upper curved portion of the stomach.
    Cheeks
    Lateral walls of the oral cavity composed of muscle and fat.
    Sigmoid Colon
    S-shaped final segment of the colon.
    Laryngopharynx
    Lower part of pharynx leading to esophagus.
    Submandibular Glands
    Salivary glands beneath the mandible.

    Stomach

    Reviewed by our medical team

    Muscular sac that begins digestion of protein.

    Overview

    The stomach is a muscular, hollow organ of the digestive system that plays a central role in the mechanical and chemical breakdown of ingested food. It serves as a reservoir where food is mixed with gastric secretions to form chyme, which is gradually released into the small intestine. It also acts as a barrier, immune organ, and endocrine gland, making it essential for both digestion and systemic regulation.

    Location

    The stomach is located in the upper left quadrant of the abdomen, extending into the epigastric and sometimes left hypochondriac regions. It:

    • Lies below the diaphragm, posterior to the left lobe of the liver

    • Is anterior to the pancreas and superior to the transverse colon

    • Varies in size and position depending on the volume of contents and body habitus

    Structure

    The stomach is divided into several anatomical regions:

    • Cardia: Area around the esophageal opening

    • Fundus: Dome-shaped superior portion, usually filled with gas

    • Body (corpus): The central, largest region responsible for most mixing and secretion

    • Pylorus: Divided into the antrum and pyloric canal, it regulates passage into the duodenum via the pyloric sphincter

    Its wall has four primary layers:

    • Mucosa: Contains gastric glands and rugae (folds)

    • Submucosa: Rich in blood vessels and lymphatics

    • Muscularis externa: Three muscle layers (oblique, circular, longitudinal) for powerful mixing

    • Serosa: Outer peritoneal covering

    Function

    The stomach performs several digestive and regulatory functions:

    • Storage: Temporarily holds ingested food and regulates its release into the small intestine

    • Mechanical digestion: Churns food into chyme using coordinated muscular contractions

    • Chemical digestion: Secretes gastric juices including hydrochloric acid (HCl), pepsinogen, and intrinsic factor

    • Intrinsic factor secretion: Necessary for vitamin B12 absorption in the ileum

    Physiological Role(s)

    The stomach supports multiple physiological processes:

    • Defense: Acidic environment kills ingested pathogens and denatures harmful proteins

    • Hormonal regulation: Produces hormones such as gastrin (stimulates acid production), ghrelin (stimulates appetite), and somatostatin (inhibits acid secretion)

    • Neural integration: Works with enteric and autonomic nervous systems for coordinated motility and secretion

    • Volume accommodation: Rugae allow the stomach to stretch and accommodate large meals without increasing internal pressure

    Clinical Significance

    The stomach is frequently involved in gastrointestinal diseases and is a critical focus in endoscopic and surgical procedures:

    • Gastritis: Inflammation of the stomach lining due to infections (e.g., H. pylori), alcohol, NSAIDs, or stress

    • Peptic ulcer disease (PUD): Erosions in the gastric or duodenal mucosa caused by acid and pepsin

    • Gastric cancer: Often asymptomatic in early stages; associated with chronic gastritis, H. pylori infection, and certain dietary factors

    • Gastroesophageal reflux disease (GERD): Incompetent lower esophageal sphincter allows acid to reflux into the esophagus

    • Gastroparesis: Delayed gastric emptying due to vagus nerve dysfunction, often seen in diabetes

    • Bariatric surgery: Procedures like sleeve gastrectomy or gastric bypass alter stomach anatomy for weight loss and metabolic improvement

    The stomach is evaluated through diagnostic tools such as endoscopy, barium studies, CT imaging, and gastric pH testing. Understanding its function and pathology is essential in gastroenterology and internal medicine.

    Did you know? Food can be completely digested within 6 hours in the stomach and intestines.