Digestion, Absorption and Transport of Carbohydrates
Start with the big picture
Digestion is a staged process: salivary α-amylase starts starch and glycogen hydrolysis, gastric acid limits its activity, and pancreatic α-amylase continues breakdown in the small-intestinal lumen. Brush-border enzymes then release monosaccharides. At the intestinal surface, SGLT1 brings glucose and galactose into enterocytes with sodium, while GLUT5 transports fructose. The basolateral Na⁺/K⁺-ATPase maintains the sodium gradient that supports SGLT1, and GLUT2 carries monosaccharides toward the portal vein. The topic also connects these mechanisms to lactose and other carbohydrate malabsorption, oral rehydration, α-glucosidase inhibitors, fiber fermentation, and factors influencing glycemic index. Together, these concepts link normal digestion and absorption with clinical and dietary relevance.
What you'll learn
- Trace carbohydrate digestion from the oral cavity through the small intestine.
- Distinguish the roles of pancreatic and brush-border carbohydrate-digesting enzymes.
- Identify the intestinal transporters involved in monosaccharide uptake and exit.
- Relate selected transporter or enzyme defects to carbohydrate malabsorption.
- Describe clinical and dietary connections, including oral rehydration and fiber fermentation.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
