scientos

Hello When antibodies are floating, they do not trigger any immune reaction. However, when an antigen is bound to the antibody, then the resulting complex activates immune reactions. How exactly these complexes trigger immune reactions? I think it is via their Fc fragment but what is the difference between a free antibody and an antibody with antigen bounded, so that the one does not trigger immune responses while the other does? Thanks!

Hello! Is the blood supply to an organ done exclusively by one (or more) distinct arteries or there is extensive collateral supply from different arteries? For example, is lungs' circulation only from bronchial and pulmonary arteries/veins or there is collateral blood circulation as well from other arteries? Any examples? Let's say you want to completely block blood supply to prostate. If you block completely the prostate artery, do you achieve that? Or blood from different arteries will supply the organ? Or the same with a specific bone or with lungs or with bowel. In other words, do we know which arteries supply which organ/area and are these specific arteries or there is never one or more distinct arteries who supply one organ or region? I don't mean small vessels that may be inactive normally and activate under stress, because these branches come from the same arteries that supply the organ. I am talking about different arteries from the arteries that are supposed to supply the organ. Also, I am not talking about the variations in vasculature. I know that not all vasculature is the same to every person, but would we still have one or more specific arteries supplying a specific organ or region? Thanks!