absorption in the small intestine

• What is the primary function of the small intestine in digestion?

  To absorb the products of digestion into the bloodstream
• How are large food molecules broken down during digestion?

  They are broken down into smaller molecules by enzymes
• What enzyme digests starch into simple sugars?

  Amylase
• Why is the length of the small intestine important for absorption?

  It provides a very large surface area for absorption
• How long is the human small intestine?

  Approximately 5 meters
• What are villi and their role in the small intestine?

  Villi are small projections that massively increase the surface area for absorption
• What is the function of microvilli in the small intestine?

  To increase the surface area for absorption even further
• How does a good blood supply in the villi aid absorption?

  It rapidly removes the products of digestion, increasing the concentration gradient
• Why is a thin membrane under the villi important?

  It ensures a short diffusion path for the products of digestion
• How do the adaptations of the small intestine contribute to the rate of diffusion?

  They create a rapid rate of diffusion of the products of digestion into the bloodstream
• What process is used to absorb molecules that cannot be absorbed by diffusion?

  Active transport
• What are the key adaptations of the small intestine for absorption?

  • Long length (around 5 meters) for large surface area
  • Presence of villi to increase surface area
  • Microvilli on villi for further surface area increase
  • Good blood supply to maintain concentration gradient
  • Thin membrane for short diffusion path
  • Active transport for molecules that cannot diffuse