Tryndamere

So how do you counter a mid to late game Tryndamere? He has an extremely high amount of AD, an ability that slows you, an gap closer, and an ult that makes him unkillable for a very large amount of time. All he has to do is push down towers and when you don't have good team coordination (aka low elo), he is impossible to fight because there is nothing that can stop him other than a string of cc which isn't always available. I have absolutely no idea how to fight him without him taking out several members of my team before finally dying.