BRAINCAKEPathogenic Effects of Influenza
Once influenza viruses enter the airways, they infect and destroy the ciliated epithelial cells lining the nose, trachea and bronchi. New virus particles leave each infected cell and invade neighbouring cells, so large areas of epithelium are damaged. This produces a sore throat, a dry cough and a runny nose.
The loss of cilia means the mucociliary escalator no longer sweeps mucus and trapped microorganisms up out of the lungs. Bacteria can then settle in the lungs, so a common and dangerous complication of flu is secondary bacterial pneumonia, for example caused by Streptococcus pneumoniae. In pneumonia the alveoli fill with fluid, reducing gas exchange.
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Key terms in this lesson
- pneumonia
- Infection or inflammation of the lungs in which the alveoli fill with fluid, reducing gas exchange.
- pandemic
- An epidemic that has spread across many countries or continents.
More in Viruses, Fungi and Protozoa
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- Pathogenic Effects of Stem Rust
All 17 lessons in Viruses, Fungi and Protozoa · All Edexcel A-level Biology topics