(50) Intro to GI, Assessment, & Dx Tests NRS 101

Introduction to the Gastrointestinal System

  • Overview of the gastrointestinal (GI) system as the digestive tract or alimentary canal.

  • Muscular tube lined with mucous membrane, extending from the mouth to the anus, approximately 30 feet long.

  • Major components include:

    • Mouth

    • Pharynx

    • Esophagus

    • Stomach

    • Small intestine

    • Large intestine

    • Anus

Anatomy and Physiology Review

Peristalsis

  • Definition: Coordinated, rhythmic contractions of smooth muscle that move food through the GI tract.

Accessory Organs

  • Aid in digestion, not part of the GI tract:

    • Teeth

    • Tongue

    • Salivary glands

    • Liver

    • Gallbladder

    • Pancreas

    • Appendix

The Mouth

  • First part of the digestive system.

  • Functions: Chewing, swallowing, and speech.

  • Papillae on the tongue contain taste buds.

  • Enzymatic breakdown of carbohydrates begins here.

The Teeth

  • Types of teeth:

    • Incisors: Biting and cutting (front teeth).

    • Canines: Tearing and shredding.

    • Molars: Crushing and grinding (mastication).

Salivary Glands

  • Major glands: Parotid, submandibular, and sublingual.

  • Produce saliva (99% water).

  • Salivary secretion ranges from 1,000 to 1,500 mL daily.

The Esophagus

  • A muscular tube connecting the mouth to the stomach.

  • Food moves through the pharynx to the esophagus by peristalsis.

The Stomach

  • Located in the left upper quadrant of the abdomen (below the diaphragm).

  • Holds 1-1.5 liters, size of a football when full.

  • Cardiac sphincter (entrance) and pyloric sphincter (exit) prevent reflux.

  • Food mixes with gastric juices, forming chyme, which moves to the duodenum.

The Small Intestine

  • Length: ~20 feet, diameter: 1 inch.

  • Comprised of three sections:

    • Duodenum

    • Jejunum

    • Ileum

  • Site of 90% of digestion and metabolism of carbohydrates and proteins.

  • Contains villi for nutrient absorption.

The Large Intestine

  • Length: 5-6 feet, diameter: 2 inches.

  • Components:

    • Cecum

    • Appendix

    • Ascending, transverse, descending, sigmoid colon

    • Rectum

    • Anus

  • Functions: Water absorption, vitamin production, fecal formation, and expulsion.

The Liver

  • Located under the diaphragm in the upper right quadrant.

  • Divided into two lobes, receives 1,500 mL blood/min.

  • Produces bile for fat digestion, stored in gallbladder.

  • Numerous metabolic functions detailed on page 1395 of the foundations book.

The Gallbladder

  • Pear-shaped organ attached to the liver.

  • Main function: Store and eject bile to aid fat digestion.

The Pancreas

  • Located posterior to the stomach.

  • Produces digestive enzymes (protease, amylase, lipase) and sodium bicarbonate for acid neutralization.

Assessment and Diagnostic Tests

Health History Assessment

  • Key topics to explore:

    • Abdominal pain

    • Bowel pattern changes

    • Weight fluctuations

    • Previous GI disorders/surgeries

    • Medication history (e.g., NSAIDs, vitamins, herbal supplements)

    • Nutritional assessment, including dietary history and allergies.

Physical Assessment

  • Evaluate general appearance for nutritional/metabolic signs:

    • Hair texture

    • Eye condition

    • Oral health (teeth, gums, tongue)

    • Skin and nails appearance

    • Muscle tone

    • Ability to chew and swallow (gag reflex).

Height and Weight Assessment

  • Proper procedures for accurate measurement:

    • Best to weigh in the morning after using the bathroom.

    • Ideal body weight calculations based on height:

      • Female: 100 lbs + 5 lbs per inch over 5 feet.

      • Male: 106 lbs + 6 lbs per inch over 5 feet.

  • Definitions of nutrition status:

    • Malnutrition: 10-20% below ideal body weight.

    • Overweight: 10% above ideal body weight.

    • Obesity: 20% or more above ideal body weight.

Oral Assessment

  • Inspect and palpate lips, tongue, buccal mucosa, teeth, and gums for signs of deficiency or infection (e.g., angular cheilitis, glossitis, candidiasis).

Abdominal Assessment

  • Steps:

    1. Inspect abdomen for contour and symmetry.

    2. Auscultate to listen for bowel sounds (normal, hypoactive, hyperactive).

    3. Palpate all quadrants for pain, distention, or masses.

    • Note the presence of rebound tenderness.

Laboratory Tests

Liver Tests

  • Serum albumin, bilirubin, liver enzymes (ALP, ALT, AST, GGT), protein, and ammonia levels.

Pancreatic Tests

  • Serum amylase and lipase to assess pancreatic function.

Diagnostic Tests Overview

  • Upper GI tests: UGI series, gastric analysis, EGD, capsule endoscopy, barium swallow, and esophageal function studies.

  • Lower GI tests: Occult blood tests, sigmoidoscopy, barium enema, colonoscopy, stool cultures, obstruction series.

  • Accessory organs tests: Cholecystography, intravenous cholangiography, liver biopsy, and ultrasound.

Conclusion

  • Encourage students to reach out with questions or clarifications via email or during the Q&A session.