Question

The "COVID-19 Animation" video simplifies what happens inside your lungs during a Corona virus infection. The replicating virus does not directly fill your lung alveoli with fluid (i.e. a virus does not create fluids). Based on what you have learned about virus replication and your immune system, why does a patient with Corona virus get fluid in their alveoli in their lungs? (4 points) For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac).

Answer 1

Lungs consists of bronchi which divides into many branches called bronchioles. at the end of each bronchiole, there is a tiny sac like structure called alveoli. These are meant for gaseous exchange (CO2 and O2). Lungs are majorly responsible for exchange of gases.

When there is a viral infection, the virus interacts with mucous membrane lining of the nose, mouth and eyes. The virus enters into a healthy cell and using the host machinery, replicates itself and produces multiple copies of new viral particles that infect surrounding healthy tissues. The coronavirus is able to infect both upper and lower respiratory tract. During the coronavirus infection, the immune system tends to fight against the virus, thereby recruiting immune cells at the site of infection for example- alveolar surfactant proteins, alveolar macrophages. The extravasation of immune cells causes chronic inflammation in the air sacs/ alveoli of the lungs. This inflammation activates various cytokines IL-1 (interleukin-1), IL-8 (interleukin-8), TNF (tumor necrosis factor). Theses cytokines recruits neutrophils and promote chemotaxis at the site of infection resulting into leukocytosis and purulent secretion (it is sputum that consist of viscous fluid/ pus, dead tissues, serous fluid, mainly WBCs and debris of cells). This is the reason when COVID-19 infection occurs, there is pneumonia like fluid filled in alveoli of lungs.