Lymph nodes often swell during an infection because
- A. they fill with excess tissue fluid
- B. bacteria dissolve inside them
- C. lymphocytes multiply rapidly inside them to fight the pathogen
- D. their valves close and trap lymph
Explanation
Trapped antigens trigger lymphocyte proliferation within the node, enlarging it and making it tender. Swollen glands in the neck during a sore throat are immune factories at work, not fluid accumulation.