Hey Swampman,
My science courses normally have 3 midterms and a final - so we have an exam every 2-3 weeks - which is beyond horrible... I love the social science classes I'm in (criminal justice/sociology) in which there are normally one midterm and one final - with some professors substituting a paper for the midterm or final. What's worse about the science classes on the quarter system are 5 hours of lab a week, 3-4 hours of lecture (4 or 5 units/class) with quizzes in lab that at times overlap with the midterm exams... ugh.
The quarter system is difficult to get used to, but since my school is a 4-quarter school, by going to school for one summer, I'll be graduating with my BS in 3 years. Congrats on getting accepted to med school and I hope you enjoy the quarter system!!