Explain blood capillaries in a villus
Connect nutrient removal with continued absorption.
Extended only (Supplement); Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked
Before you begin
- Recall large and small nutrient molecules, cell membranes and enzyme specificity.
- Use the stated diagram keys and evidence; models are not to scale.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which product is carried by blood capillaries after absorption?
What you will learn
- Connect nutrient removal with continued absorption.
- Use a nutrient balance without confusing removal with the crossing mechanism.
Blood carries soluble products away
Villus blood capillaries receive absorbed glucose and amino acids and carry them away for distribution. Flow removes products from near the absorptive surface, helping maintain concentration differences for relevant transport processes.
Blood flow is not a digestive enzyme and does not itself break starch down. The nutrients first need the relevant digestion and transport pathways; capillaries then provide a removal route.
Use a supplied comparison
A model with continued flow can remove absorbed product while a closed no-flow reservoir accumulates it. This illustrates removal but does not reproduce every transporter, tissue or real-body concentration.
Do not claim all absorption is simple diffusion. Some processes use carrier-mediated transport, including active transport. Explain the capillary role as uptake and carriage, rather than replacing the transport mechanism with an unsupported universal rule.
Pause and explain
Why is product removal useful?
Worked example
A villus capillary carries glucose away from the intestinal lining. Explain how removal can support continued uptake.
Show the worked solution
- Blood removes absorbed glucose.
- It limits local accumulation.
- This can help preserve a concentration difference for appropriate transport.
Answer Capillary flow carries products away and helps sustain conditions supporting further absorption.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State the roles of villus capillaries for glucose and amino acids.
Give me a hint
Use receive and carry away.
Compare my reasoning
- Receive absorbed products.
- Transport them away in blood.
They receive absorbed glucose/amino acids and carry them away for distribution.
Look for these in your work
- Products named.
- Transport role.
In a teaching model, 12 arbitrary nutrient units enter a blood compartment and 9 leave in the same interval. Find its net accumulation.
Give me a hint
Input minus output.
Compare my reasoning
- 12 − 9 = 3.
- Retain model units.
3 units accumulate; outward transport removes 9 of the incoming units.
Look for these in your work
- Correct balance.
- No invented physiological rate.
A student says capillary flow proves every nutrient crosses by passive diffusion. Evaluate.
Give me a hint
Removal route does not identify every membrane transporter.
Compare my reasoning
- Flow describes carriage/removal.
- Membrane transport mechanisms differ.
The conclusion is unsupported; capillary flow does not prove that all uptake is passive diffusion.
Look for these in your work
- Separate carriage and crossing.
- Avoid universal mechanism.
Common mistakes
- Blood flow is not chemical digestion.
- Not every absorbed nutrient uses simple diffusion.
What can you explain now?
Why is product removal useful?
Compare with the explanation
It reduces local accumulation near the absorption surface.
Flow helps maintain appropriate uptake conditions.
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Make it stick
Explain how capillary flow differs from digestion and membrane transport.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.