The gut moves and digests food while accessory organs provide secretions.
NIH institute overview of the tract, organ contributions, peristalsis and absorption.
NIDDK · Digestive systemBreak it down. Then cross the boundary.: sources & model
Follow a meal through the gut, then zoom into its lining. Choose starch, protein or long-chain fat and discover why their next routes differ.
Scientific review · independent subject review pending
The source and model records are available for inspection. No external scientific reviewer has signed off yet.
digestion-1 · content 1 · setup format 1What supports the explanation?
Selected long-chain lipids enter lacteals; sugars and amino acids enter capillary routes.
Nutrient-specific discussion and table 23.10 distinguish lipid routes and short-chain exceptions.
OpenStax · Digestion and absorptionMechanical digestion, chemical digestion, propulsion and absorption are distinct.
Academic definitions and mechanism descriptions.
OpenStax · Digestive processesWhat this model assumes
- Selected healthy-human pathways. The torso image is an illustrative context asset, not a medical scan or the basis of numeric anatomy.
- The animated tract is spatially simplified and the villus is greatly enlarged. Moving parcels indicate a selected route, not measured flow or a complete nutrient balance.
- No clinical, dietary, transit-time, calorie or individual absorption prediction.
- Surface area is useful: Small-intestinal folds, villi and microvilli increase exchange area at distinct scales. The magnified villus shows lumen, lining, capillary and lacteal. A villus is not a single cell, and it is not the same structure as a microvillus.
- Emulsification is not bond cleavage: Bile helps disperse lipid droplets, increasing access for digestion. That physical process is different from an enzyme cleaving a molecule. In the virtual route, a label identifies the selected product rather than pretending every nutrient is the same bead.
- A pathway is not a personal forecast: Transport depends on nutrient species and cellular mechanisms. The selected routes do not cover all substances, uptake mechanisms or real motility. The progress bar names stages, not a universal digestion time, calorie calculation or blood-sugar response.
What has been checked
Analytical reference cases, conservation or transition invariants, finite drawing commands, bounded setup parsing, discovery and route integrity are checked automatically. These checks do not establish anatomical fidelity, learner outcomes or browser/device compatibility. Independent subject review, learner trials, comprehensive accessibility review and browser video encoding checks remain pending.
Each source supports the associated claim. Sources do not certify this implementation or its visuals.
About the cover illustration
The topic card uses an AI-generated editorial illustration. It introduces the subject; it is not a validated anatomical reference or a measured landscape. The experiment’s diagrams, readouts and assumptions explain the model separately.
Our review process