Where are you studying Med Science?
Because, there are different majors that you can choose - and those majors will effect what you study.
In most majors, you don't need to know physics.. but biology and chemistry will be useful to know, as most majors delve into bio and chem, whereas I think only one (nanotechnology) really goes into physics.
I think that there is definitely an expected degree of knowledge/assumed knowledge, that you will have to know. Some med science courses have units known as "scientific literacy" which can delve into some of the basic knowledge, but I think to be safe, you should probably invest some time in reading over some year 12 bio and chem if you can.