Digestive

Digestive System Overview

  • The digestive system performs vital functions by breaking down food, absorbing nutrients, and eliminating waste.

  • Key components include the mouth, esophagus, stomach, small and large intestines, liver, pancreas, and gallbladder.

Learning Objectives

  • Apply Medical Language Rules: Help build, analyze, spell, pronounce, and define terms related to the digestive system.

  • Identify Key Components: Recognize and understand the keywords associated with the digestive system.

  • Categorize Terms: Classify diagnostic, therapeutic, procedural, and anatomic terms.

  • Utilize Terminology: Use appropriate terms for diseases and disorders affecting the digestive system.

Introduction to the Digestive System

  • The body is largely unaware of the digestive processes occurring after food intake unless there's a complication (e.g., stomachache).

  • The digestive system works to breakdown foods, process nutrients, and use the ingredients for bodily functions until waste is excreted.

Main Functions

  • Breaks down food substances.

  • Releases nutrients for absorption into the bloodstream.

Digestive System Components

  • Organs Involved:

    • Mouth

    • Esophagus

    • Stomach

    • Small Intestine

    • Large Intestine

    • Anus

    • Accessory Organs: Liver, Gallbladder, Pancreas.

Anatomy of the Digestive System

Mouth

  • Oral cavity framed by cheeks, tongue, and palate.

  • Parts:

    • Oral Vestibule: area between gums/teeth and lips/cheeks.

    • Palate: arched structure allowing simultaneous chewing and breathing.

    • Uvula: prevents food from entering the nasal cavity while swallowing.

Salivary Glands

  • Minor glands in the mouth secrete saliva (1-1.5 liters/day), which helps moisten food and initiate carbohydrate digestion.

Pharynx

  • The throat, functioning in both respiration and digestion, guides food to the esophagus while closing off airway.

Esophagus

  • Muscular tube connecting pharynx and stomach, controlled by the upper and lower esophageal sphincters to manage food flow.

Stomach

  • Consists of four regions:

    • Cardia: connects to the esophagus.

    • Fundus: dome-shaped top of the stomach.

    • Body: main section.

    • Pylorus: connects to the duodenum.

Small Intestine

  • The primary site for nutrient absorption, approximately 10 feet long. Divided into three regions:

    • Duodenum

    • Jejunum

    • Ileum

Large Intestine

  • Responsible for finishing nutrient absorption and water regulation, synthesizing vitamins, and forming feces. Contains:

    • Cecum: initial pouch receiving contents from the ileum.

    • Colon: divided into ascending, transverse, descending, and sigmoid sections.

    • Rectum and Anus: controlling fecal elimination.

Accessory Digestive Organs

Liver

  • Largest gland, producing bile for fat emulsification, filtering blood for nutrients, drugs, and toxins.

  • Bile gives color to stool via bilirubin breakdown.

Pancreas

  • Functions as exocrine (produces digestive enzymes) and endocrine (hormonal regulation) organ.

  • Located behind the stomach and contributes to digestion via pancreatic juice.

Gallbladder

  • Stores and concentrates bile until needed for digestion in the small intestine.

Digestive Physiology

Main Functions

  • Ingestion: Entry of food through the mouth.

  • Propulsion: Movement through swallowing and peristalsis.

  • Mechanical Digestion: Includes chewing and stomach mixing.

  • Chemical Digestion: Breakdown of food by enzymes in the mouth, stomach, and small intestine.

  • Absorption: Nutrients taken into the bloodstream, mainly occurring in the small intestine.

Medical Specialties and Procedures

  • Gastroenterology: Field focused on digestive system issues.

  • Procedures: Upper & Lower GI series, stool culture, EGD for diagnosing digestive disorders.

Diseases and Disorders of the Digestive System

  1. Gastroesophageal Reflux Disease (GERD): A condition characterized by the regurgitation of stomach acid into the esophagus, leading to a burning sensation.

  2. Cholecystitis: The inflammation of the gallbladder, commonly due to the presence of gallstones.

  3. Cirrhosis: A disease in which the liver becomes severely scarred, often as a result of chronic liver disease or excessive alcohol consumption.

  4. Hepatitis: This refers to liver inflammation that can occur due to various causes, including viral infections, toxins, or autoimmune diseases.

  5. Irritable Bowel Syndrome (IBS): A functional disorder of the colon that manifests with symptoms like abdominal discomfort, bloating, and gas.

  6. Celiac Disease: An autoimmune condition where ingestion of gluten leads to intestinal damage.

  7. Colon Cancer: A form of cancer that originates in the colon or rectum, often manifesting with symptoms like changes in bowel habits or abdominal discomfort.

  8. Esophageal Cancer: Cancer that occurs in the esophagus, typically presenting with symptoms such as difficulty swallowing, weight loss, and chest pain.