If you go to
https://medicine.umich.edu/medschool/education/md-program/our-community/students-faculty/admitted-class-profile
you can see the undergraduate colleges of the medical students at the University of Michigan in each year.
Clicking on the earlier year’s data, you can see for example for the entering class in 2018, 47 were undergraduates at the University of Michigan, and two or fewer came from Central Michigan.