Disease symptoms are sometimes the result of your immune system doing its job. You often hear that bacteria, viruses and fungi are the cause of disease symptoms, but this is technically incorrect. Disease symptoms sometimes occur because your immune system is reacting to the microorganisms. For example, take the common cold. Your immune system jumps into action when the rhinovirus invades the epithelial cells — cells that line the cavities in the body — in your upper respiratory tract. Immune system chemicals called histamines dilate your blood vessels and increase their permeability, allowing proteins and white blood cells to reach the infected epithelial tissues. However, the inflammation of the blood vessels in your nasal cavity causes nasal congestion. Additionally, you may get a runny nose because of the increased fluid leakage from your permeable capillaries, combined with an increased mucus production triggered by the histamines. To know more facts on Immunology join us on
