COVID-19 - How does it affect you? Gas Exchange Each sac of air, or alveolus, is wrapped with capillaries where red blood cells release carbon dioxide (CO2) and pick up oxygen (O2). Two alveolar cells facilitate gas exchange; Type I cells are thin enough that the oxygen passes right through, and Type II cells secrete surfactant — a substance that lines the alveolus and prevents it from collapsing. Viral Infection The spike proteins covering the coronavirus bind ACE2 receptors on type II alveolar cells, allowing the virus to enter the cell via endosome or membrane fusion and release its RNA. The RNA "hijacks" the cell, telling it to assemble many more copies of the virus and release them into the alveolus. The host cell is destroyed in this process and the new coronaviruses infect neighbouring cells. Avesta Rastan @azuravesta #COVID19 #Pathophysiology #SARSCOV2 #PatientInfo
