Based on a typical 2 year curriculum, there is not a lot of MS1 material tested directly on step 1. However, a lot of MS2 builds on MS1. If you don't know abdominal anatomy, you won't be able to make a differential for RUQ pain, you won't know why luminal perfs cause shoulder pain, you would understand why posterior duodenal ulcers can cause hemorrhage, etc. If you don't know basic fluid dynamics/physiology pretty much nothing in cardio will make sense to you. If you don't know neuroanatomy none of the strokes or brainstem lesions will make sense to you.
Basically if you don't understand MS1, MS2 will be 100% memorization and you'll want to blow your brains out.
Sorry if this sounds mean, but "Does one really have to go through the whole BRS Physiology?" is hilarious. BRS physiology is such a short book with only the highlights of physio. It's like the FA of physiology. You should already know everything in it by the time MS2 is over, but if you don't it is something to flip through.
