New to the Hospital. What are the differences between the following units?

I am in a BSN program, and have been accepted into a summer training program at a local hospital. This program is designed to help students learn more about the hospital setting. Students get to pick an area to work in, so I want some information regarding the following.

This hospital has med/surg units, plus serpate general medical units, and general surgery units. What are the differences between the three, and what would a nurse tech do differently on the three.

Also does anyone know what MOB-ASC, or OPAD stands for. There are openings for students in these areas, but I do not know what they are.

I don't want to request a unit before I get a graps on the details and duties.

Please, please help.

Joy