So respiratory viruses like the cold, flu, and covid enter the body through the nasal passages and not through the blood stream. Since the white blood cells are in the blood stream, how do they get to the virus to fight it?
In: 3
You blood vessels feed capillaries, much smaller tubes that worm their way into all your tissues. At the very end, blood cells must cross through the tissue and back into another capillary that returns them to the main circulatory system.
The red cells have to get within touching distance of just about every cell so that they can deliver oxygen, so at the cellular level all your tissues are webbed with these capillaries.
The immune cells also patrol this network, and will stop and linger in one location if they’re “flagged down” by a cell in distress.
When one of your cells gets infected by a virus, it attempts to self destruct and spew warning chemicals out to alert all the immune cells nearby.
Some particularly devious viruses can disable this mechanism, it’s a constant evolutionary battle.
Latest Answers