Absorption：练习题

Which part of the human alimentary canal is the primary site for the absorption of most digested nutrients and water into the blood?

Which part of the human alimentary canal contains the highest density of microvilli to maximize the rate of absorption?

Which row correctly identifies the primary destination for the listed nutrients after they cross the epithelium of a villus?

Which part of the digestive system is the main region for the absorption of digested nutrients?

A student observes a micrograph of a villus. The image height of the villus is measured as \(12\) mm. If the actual height of the villus is \(400\) \(\mu m\), what is the magnification used?

State the name of the tissue layer, often only one cell thick, that forms the outer surface of a villus through which all nutrients must pass during absorption.

Explain how the epithelium of a villus being only one cell thick aids in the efficient absorption of digested food molecules.

The small intestine is highly adapted for absorption through multiple levels of folding. Distinguish between the structural contributions of villi and microvilli in this process.

(a) State the region of the human digestive system where most digested nutrients are absorbed.
(b) Describe the structural adaptations of a villus that increase the efficiency of nutrient absorption.
(c) Explain the specific roles of the capillaries and lacteals found within the villi during the absorption process.

The small intestine is approximately 5 meters long in an adult human.
(a) Explain why the length of the small intestine is a structural advantage for the process of absorption.
(b) Distinguish between villi and microvilli in terms of their size and their specific location in the ileum.
(c) Suggest how a high-fiber diet might affect the total time available for absorption as material moves through the alimentary canal.