As others here have said, your undergrad doesn't matter too much as long as you did well there.
The rule of thumb is that people who went to high powered undergrads have a small amount of leniency when it comes to their grades but not more than .1 GPA if even that much. However, there are some med schools (particularly ivies) that greatly prefer students who come from renowned undergrads. Harvard, Stanford, Columbia, UPenn, and Yale come to mind as examples. If you're not dying to get into those schools though, you shouldn't worry about it.