CPR APPLICATIONS FOUNDATION · CHAPTER 13 · NORMAL
Normal Foundations of the Gastrointestinal System
Organize the chapter before drilling into individual CPR concepts.
Supplemental foundation map: this page orients the detailed CPR Applications for Chapter 13. It is not part of the canonical CPR object inventory.
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Normal Foundations · You are here
Abnormal Foundations
Treatment Foundations
13.1 · SOURCE CPR FOUNDATION
Concept
The GI system is a sequential flow network where each segment performs a distinct job. Disease becomes easier to localize when you ask what is missing, retained, backed up, or spilling into the wrong compartment. The liver, gallbladder, and pancreas modify digestion, absorption, metabolism, and elimination.
Pattern
Step 1 often gives an output clue like steatorrhea, B12 deficiency, dark urine, pale stools, ascites, or varices and expects reverse localization. Small bowel disease tends to present through malabsorption, pancreatic disease through maldigestion, and hepatobiliary disease through bilirubin-flow or portal-pressure patterns.
Rule
- Name the failing segment first. The location usually predicts the missing nutrient or backed-up product.
- Separate malabsorption from maldigestion. Small bowel mucosal disease impairs absorption; pancreatic disease impairs breakdown.
- Use bilirubin and pressure patterns to localize hepatobiliary disease. Conjugated hyperbilirubinemia suggests impaired hepatobiliary excretion or flow, which may be intrahepatic or extrahepatic; portal hypertension produces venous congestion.
Applications
- Terminal ileum resection → B12 deficiency and bile acid diarrhea
- Pancreatic insufficiency → steatorrhea and ADEK deficiency
- Lactose malabsorption → osmotic diarrhea and bloating after lactose exposure; isolated intolerance does not usually cause major systemic malabsorption
- Celiac disease → iron deficiency and systemic malabsorption
- Obstructive jaundice → dark urine pale stools conjugated bilirubin
- Portal hypertension → varices ascites splenomegaly
- Tip: Localize by what is missing or backed up
CPR APPLICATIONS · ACTIVE REASONING
Locate digestion and absorption
Make a prediction first. Each worked answer is available without JavaScript. These exercises do not save or send responses.
Worked reasoning and transfer
Best answer: Vitamin B12 and bile acid absorption. The ileum is important for intrinsic factor–B12 uptake and bile acid recycling.
Transfer: How might bile acid loss affect stool?
Worked reasoning and transfer
Best answer: Fat maldigestion and steatorrhea. Reduced pancreatic enzymes impair fat digestion.
Transfer: What fat-soluble vitamins may become low?
Worked reasoning and transfer
Best answer: Conjugated hyperbilirubinemia with impaired bile delivery. Water-soluble conjugated bilirubin enters urine; reduced intestinal pigment can pale stools.
Transfer: Can intrahepatic cholestasis also cause this?
Explain it back: Write a causal chain for one decision, then identify which piece of evidence would change the answer.
Unscored teaching examples; not validated assessment items or patient-specific advice.
How to use this foundation map
- Identify the organizing mechanism.
- Recognize the pattern.
- Restate the rule without looking.
- Test transfer with applications and question practice.
Pair CPR with the 5P Approach™ when solving cases and questions.