Why does spleen enlarge in a patient suffering from infections due to invasion of pathogens?

Explanation

### Step-by-Step Solution:

1. **Understanding the Spleen's Function**: The spleen plays a crucial role in the immune system. It helps filter blood and remove pathogens, such as bacteria and viruses, from the bloodstream. It also produces and circulates antibodies that are essential for fighting infections.

2. **Pathogen Invasion**: When a person is infected by pathogens (bacteria, viruses, etc.), these invaders enter the bloodstream. The body recognizes these pathogens as harmful and activates the immune response.

3. **Increased Blood Flow to the Spleen**: In response to an infection, the body increases blood flow to the spleen. This is part of the immune response, as the spleen needs to work harder to filter out the pathogens and produce antibodies.

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