Gastrointestinal System and Related Health Issues

  • Pre-Quizzes in Education

    • Educational psychology supports the use of pre-quizzes to enhance learning.
    • They aid memory formation, preparing students for discussion in lectures.

  • Gastrointestinal (GI) Tract Overview

    • Major Functions:
    • Digest food
    • Absorb nutrients
    • Motility through peristaltic waves
    • Secretion of about 9 liters/day of fluids, enzymes, and bile into the GI tract; only 6 ounces are reabsorbed by the body.
    • Digestive Process:
    1. Ingestion: Mouth, esophagus, stomach (first digestion)
    2. Absorption: Small intestine (duodenum, jejunum, ileum - 90% absorption occurs here)
    3. Elimination: Large intestine (colon)

  • Structure of the GI Tract:

    • Upper GI: Mouth, esophagus, stomach
    • Middle GI: Duodenum, jejunum, ileum (total of about 9 feet long)
    • Lower GI: Cecum, colon (1.5 feet long)
    • Over 2-6 pounds of bacteria reside in the colon contributing to immune function and digestion.

  • Digestive Health and Bacteria:

    • Role of bacteria in digesting vitamins like Vitamin K and D.
    • Ileocecal valve prevents backflow into the small intestine, essential for maintaining gut health.

  • Accessory Organs:

    • Liver: Produces bile and performs detoxification; knowledge of liver anatomy is crucial.

  • Emesis (Vomiting) Process:

    • Involves multiple systems: the sympathetic system can trigger vomiting due to pain or anxiety.
    • Emetic reflex controlled by various brain areas including the medulla.

  • Types of Diarrhea:

    1. Osmotic Diarrhea: Caused by poorly absorbed solutes that pull water, e.g., lactose intolerance.
    2. Secretory Diarrhea: Triggered by toxins or infections, e.g., cholera leading to severe fluid loss.
    3. Altered Motility: Increased peristalsis due to stress.

  • Abdominal Pain:

    • Dull, squeezed pain (visceral) varies according to organ involvement (e.g., sharp pain indicates inflammation).

  • Esophagus:

    • A collapsible tube (~10 inches) with a critical role in swallowing and peristaltic motion.
    • Dysfunctional signs include dysphagia (difficulty swallowing) and achalasia (failure of lower esophageal sphincter to relax).

  • Gastroesophageal Reflux Disease (GERD):

    • Caused by relaxed lower esophageal sphincter allowing stomach acid to penetrate the esophagus.
    • Symptoms include burning chest pain and potential heart attack mimicking symptoms.

  • Peptic Ulcers:

    • Erosion in the wall of the GI tract popular in the stomach and duodenum.
    • Risk factors include H. pylori, NSAIDs, and smoking.

  • Inflammatory Bowel Disease (IBD):

    • Crohn's Disease: Can affect any GI area with skip lesions, causing abdominal pain, diarrhea, and malabsorption.
    • Ulcerative Colitis: Affects only the colon, leading to bloody diarrhea and increased cancer risk.
    • Both conditions show an immune response to gut bacteria, could be triggered by antibiotics or diet.

  • Cholecystitis and Cholelithiasis:

    • Cholecystitis: Inflammation of the gallbladder, usually from a blocked bile duct.
    • Cholelithiasis: Formation of gallstones, increasing risk from obesity and diet.

  • Pancreatitis:

    • Acute: Reversible inflammation usually due to gallstones or alcohol; symptoms include severe upper abdominal pain and fever.
    • Chronic: Irreversible damage from repeated inflammation leading to diabetes over time.

  • Liver Overview:

    • Largest internal organ, performs vital detox and metabolic functions (e.g., synthesizing bile, blood clotting factors).
    • Hepatitis can arise from several viral sources, leading to liver inflammation, jaundice, fatigue.

  • Cirrhosis:

    • End-stage liver disease with significant fibrosis often due to chronic alcohol use or fatty liver disease (NAFLD).
    • Complications include portal hypertension, ascites (fluid accumulation), and risk for liver cancer.