Use Audio port as input and output

I have a Macbook Pro 2011, running OS X Yosemite. I am trying to use my headphones, which contain a mic and speakers (as most headphones do). However, I can only use the audio jack as input or output. I have tried to change it, but whenever I go to the sound menu to select it, it only gives me Input or Output.

See:

Is there really a reason why this audio port cannot be used as both at the same time? Did I mess something up? Is there a third party method to use it as both at the same time?