Lymph is often described as 'returned tissue fluid.' (i) Explain how lymph is formed from blood plasma. (ii) State two ways in which the lymphatic system contributes to the body's functioning beyond simply returning fluid to the blood.
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
(i) Formation of Lymph:
Blood plasma, along with some proteins and blood cells, seeps out through the pores in the thin walls of capillaries into the intercellular spaces of tissues. This collected fluid in the intercellular spaces is called tissue fluid or lymph. It is colourless and contains less protein than blood plasma.
(ii) Two additional functions of the lymphatic system:
- It carries digested and absorbed fat from the intestine and transports it to the blood.
- It drains excess fluid from extracellular spaces back into the blood, maintaining fluid balance in tissues.
Source: Chapter 5, Section 5.4.1 – Lymph
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Explanation
- Part (i) expects you to link capillary permeability → plasma leakage → tissue fluid = lymph. Mention "less protein" and "colourless" for full credit.
- Part (ii): The textbook explicitly states two functions of lymph — fat transport from intestine and draining excess fluid. These are the expected points; don't invent others.
- Examiners look for the word intercellular spaces in part (i) and both distinct functions in part (ii).