What fluid, produced by tissue inflammation, contains white blood cells, bacteria, and dead cells?

• A. Blood
• B. Pus
• C. Serum
• D. Toxins

Answer: (B)

During tissue inflammation, immune cells flood to the site to fight infection. The most active players, neutrophils, engulf bacteria and debris, and as they do, they die along with the bacteria and damaged tissue. The result is a thick, yellowish or greenish fluid that collects at the site—pus. This fluid contains white blood cells, bacteria, and dead cells, and it signals an infection or pus-forming inflammation such as an abscess. In a salon setting, the appearance of purulent drainage means you must use proper PPE, discard contaminated materials safely, and thoroughly clean and disinfect surfaces to prevent spread. Blood, serum, and toxins aren’t this fluid: blood is the circulating component of the blood, serum is the liquid that remains after blood clots, and toxins are harmful substances—not a fluid produced by inflammation.