You might be surprised, but their remaining kidney is actually working harder to make up for the loss of the donated kidney.
assistant
Oh, I see. Well, that’s because donating one kidney is like donating part of your liver, which also allows you to function normally afterwards, as long as you take precautions and have follow-up treatment.
assistant
How come people can survive with only one kidney if they have two? What is the evolutionary reason why we have an extra kidney?
user
I don’t think you really have an extra kidney! You have two kidneys that are able to function separately, each doing their share of the work. The second kidney is there as a backup, so that if the first one fails, the second one can keep working and maintaining your health.
assistant
I was asking in the context of how people often donate their kidneys and still function well.
user
So they’ll donate one kidney?
assistant
Yes, that happens frequently.
user