Work History / Professional Experience Section of US Grad School Application - Listing Research Internships I'm applying to biomedical sciences Ph.D. programs, and the applications typically allow me to type in my "Work History / Professional Experience."

I know that undergraduate research would not fall under this category, and technically internships would. However, my internships were both in research (over the past 2 summers). They were full-time positions. One took place at a hospital while the other took place at a medical school. Should I bother listing them in the work/professional experience section, especially if the application does not allow me to submit a CV/resume? I don't know if the schools want me to list any type of research here, even though both were work experiences outside of my undergraduate university.
List them anywhere reasonable rather than not listing them at all. Probably you can give short descriptions so that there is no misunderstanding. 

But let the reader judge the significance rather than assuming that they aren't worth listing. Err on the "say more" side rather than "say less". 

And, if you can send a Statement of Purpose, mention there how those things support the sort of thing you want to do.