Medical School MD + DO Mastery

A 4-year, board-aligned study system for medical school and licensing exams.

Walk the full Year 1–4 curriculum — foundational sciences, organ-system blocks, clinical clerkships and advanced practice — each with mastery checklists and linked learning resources, plus a dedicated review system for school exams, Shelf/COMAT, USMLE Step 1–3 and COMLEX-USA Levels 1–3.

YEAR 2 SYSTEMS REVIEW - GI / LIVER / NUTRITION

YEAR 2 | PAGE 48A - MOTILITY / ABSORPTION -> DISEASE LOCALIZATION -> LIVER / PANCREAS -> NUTRITION

GI SPINE: MOTILITY / SECRETION -> DIGESTION -> ABSORPTION -> PORTAL / LYMPHATIC TRANSPORT -> HEPATIC PROCESSING. LOCALIZE THE COMPARTMENT FIRST; THEN USE STOOL, LAB, IMAGING OR ENDOSCOPY CLUES TO NAME THE PROCESS. A. GI / HEPATOBILIARY CLOSED-BOOK REVIEW MAP

LANE	MUST RETRIEVE WITHOUT NOTES	HIGH-DISCRIMINATION TRANSFER
Motility + secretion	Enteric/autonomic control; gastrin, histamine, acid, secretin, CCK, GIP; pancreatic and biliary secretion.	Predict what happens when a hormone, nerve pathway, acid source, enzyme source or bile pathway is blocked.
Digestion + malabsorption	Carbohydrate/protein/fat digestion; pancreatic enzymes; bile salts; brush border; transporters; ileal recycling.	Use stool phenotype + deficiency pattern + anatomy to separate enzyme, bile, mucosal and transporter failure.
Inflammatory + bleeding	IBD, celiac, obstruction, peptic disease, diverticular disease, upper/lower bleed, colorectal pathology.	Localize by pain/stool/bleeding pattern and decide when stabilization precedes diagnostic localization.
Liver / biliary / pancreas	Hepatocellular vs cholestatic injury, bilirubin, synthetic function, portal HTN, gallstone disease, pancreatitis.	Interpret AST/ALT, ALP, bilirubin, albumin/PT and imaging as a pattern rather than isolated values.
Nutrition	Macro/micronutrient deficiency, malnutrition/refeeding, fat-soluble vitamins, alcohol-related risk.	Link the failed absorption/processing step to the nutrient phenotype instead of memorizing deficiency lists.

B. TOP 10 MOST-MISSED SYSTEM CONCEPTS - #1 TO #3

# / CONCEPT	DEEP EXPLANATION	WHY STUDENTS MISS IT	EASIEST CLUE
1. Localize GI disease before naming it	GI reasoning becomes easier when the first question is where the failure lives: esophagus/stomach, small bowel, colon, pancreas, biliary tree or liver. The same symptom can come from different compartments, but anatomy constrains the differential and test choice.	Students jump from a symptom such as diarrhea or abdominal pain directly to a disease list and miss the anatomic discriminator.	Ask which compartment must fail to produce this pattern?
2. Diarrhea / malabsorption is a mechanism problem	Osmotic, secretory, inflammatory and malabsorptive processes differ in fasting response, stool content, mucosal injury and nutrient consequences. Fat malabsorption specifically points toward bile, pancreatic lipase, mucosa or lymphatic transport.	Learners memorize named causes without linking them to what remains in the lumen or what the mucosa cannot absorb.	Think water follows what stayed in the lumen, and deficiencies reveal what was not absorbed.
3. Liver tests are pattern + function, not a single “LFT”	AST/ALT reflect hepatocyte injury; alkaline phosphatase/cholestatic markers point toward bile-flow problems; bilirubin localization matters; albumin and PT/INR reflect synthetic function over different time scales.	Students treat all liver abnormalities as interchangeable and miss the distinction between injury pattern and liver function.	First ask injury, obstruction, bilirubin handling, or synthetic failure?

C. HIGH-VALUE REVIEW RESOURCES - DIRECT + PLAYABLE

RESOURCE	ROLE IN THIS REVIEW
Dirty Medicine - GI Secretory / Regulatory Physiology	High-yield gastrin/histamine/acid, pancreatic/biliary secretion and GI hormone integration.
Ninja Nerd - GI Motility, Small Intestine	Deep motility physiology: segmentation, peristalsis, MMC and enteric control.
Ninja Nerd - Lipid Digestion + Absorption	Bile salts, pancreatic lipase, micelles, chylomicrons and enterohepatic circulation.
Ninja Nerd - Inflammatory Bowel Disease	Crohn vs UC mechanism, complications, imaging/endoscopy and treatment integration.
Ninja Nerd - Cirrhosis	Portal hypertension, synthetic failure, ascites, varices and encephalopathy.
Ninja Nerd - Liver Function Tests	Mechanism-first interpretation of injury/cholestatic patterns and bilirubin/synthetic function.

C. HIGH-VALUE REVIEW RESOURCES - DIRECT + PLAYABLE

SCHOOL-EXAM GATE	BOARD / COMLEX TRANSFER
• Explain GI hormones and digestion/absorption without notes. • Localize diarrhea, bleeding and malabsorption from the pattern before naming	• Mechanism -> stool/lab/imaging clue -> pathology -> drug/test inference. • Review low-confidence corrects involving bilirubin, malabsorption and liver patterns.
disease. • Interpret liver/pancreas/biliary labs with anatomy and mechanism. 2026/27 systems-review expanded edition - align with school objectives and verify official exam updates before testing	• Use targeted videos only when a documented mechanism remains unstable.