Chapter 5 · Question 10
How is the small intestine designed to absorb digested food?
Q10
How is the small intestine designed to absorb digested food?
Answer Revealed
Direct Answer:
The small intestine has villi, finger-like projections that increase the surface area for absorption, and a rich network of blood capillaries to transport absorbed nutrients.
Simple Explanation
The inside of the small intestine is covered with millions of tiny finger-like structures called villi. These increase the surface area so that more digested food can be absorbed into the blood quickly.
Exam-Ready Structure
The small intestine is specially adapted for absorption in the following ways: 1. Length — It is very long (about 6-7 metres in humans), providing ample time for absorption. 2. Villi — The inner lining has numerous finger-like projections called villi, which increase the surface area enormously for efficient absorption. 3. Thin walls — Each villus has a very thin epithelial layer (single-cell thickness), allowing easy diffusion of nutrients. 4. Blood capillaries — Each villus contains a dense network of blood capillaries that quickly carry absorbed nutrients to the rest of the body. 5. Lacteals — Villi also contain lymph vessels (lacteals) that absorb digested fats.
Key Points
- Long length provides time for absorption
- Villi increase surface area
- Single-cell thin walls allow easy diffusion
- Rich blood capillary network transports absorbed food
Common Mistakes
- Confusing villi with microvilli
- Forgetting that the small intestine also completes digestion, not just absorbs
Relevant Maps and Figures
Human Alimentary Canal
figure
Use the digestive tract figure to place the small intestine correctly within the full digestion pathway.
Pair it with the villi explanation when writing a three-mark answer.
This digestive tract figure is the cleanest reference for tracking how food moves from the mouth to the intestine and where digestion changes at each stage.
Answer Sources
- Absorption in the small intestinetextbook section | Science | Life Processes | Villi and nutrient absorption | Pages 8-9