Help a beginner having trouble with my If else statements

scrollUp_mc and scrollDown_mc are acting as buttons that control scroll_mc and bar_mc.
The code works fine, but I need them to stop working if scoll_mc.y is less than 136 or more than 2,189. any suggestions?

scrollUp_mc.addEventListener(MouseEvent.CLICK, goUp);
scrollDown_mc.addEventListener(MouseEvent.CLICK, goDown);

function goUp(evtObj:MouseEvent):void{
scroll_mc.y -=325;
function goDown(evtObj:MouseEvent):void{
scroll_mc.y +=325;