Digestive system ↗Amylase attacks starch
Salivary and then pancreatic amylase hydrolyze accessible starch bonds into smaller carbohydrates.
DIGESTIVE / CARBOHYDRATE
Starch becomes sugars.
Flux becomes a signal.
Carbohydrate must be digested to transportable monosaccharides. Entry rate then meets portal first-pass liver handling, pancreatic hormone responses, tissue uptake, storage, oxidation, and ongoing hepatic output.
12-STAGE ROUTE
Absorption is input,
not the final glucose value.
A blood-glucose curve is the net of appearance and disappearance. Food structure, digestion, emptying, hormones, liver output, muscle activity, medicines and health state all contribute.
Brush-border enzymes finish
Enzymes including maltase, sucrase-isomaltase and lactase produce absorbable monosaccharides.
Structure changes access
Particle size, cooking, intact cell walls, resistant starch and mixed-meal context change digestion kinetics.
Fiber follows other routes
Non-digestible carbohydrate may alter viscosity or reach the colon for partial fermentation.
Glucose and galactose enter
SGLT1 couples luminal transport to sodium gradients at the apical membrane.
Fructose uses facilitated transport
GLUT5 supports apical fructose uptake; capacity and symptoms vary with dose and context.
Monosaccharides exit basolaterally
Transport into intestinal capillaries sends sugars toward the portal vein.
The liver sees first-pass flux
Portal glucose and fructose reach hepatocytes before the systemic circulation.
Gut and pancreas signal
Glucose-dependent incretin and pancreatic responses help coordinate insulin, glucagon and gastric function.
Liver buffers supply
Hepatic glucose production normally falls while glycogen synthesis and substrate handling rise after a meal.
Tissues remove glucose
Muscle, adipose and other organs use or store glucose through tissue-specific, activity-dependent mechanisms.
The curve resolves
Systemic concentration reflects intestinal appearance minus liver and tissue disposal plus residual liver output.