Tower Graphic Glitch?

Whenever you click on a champion you get a little window in the top left hand corner, however; when you click on the tower it shows the health of the tower but has weird graphical glitches. In addition, (this is only sometimes) after the Nexus turrets fire once, the sound of the turrets firing continues to play even though it is not firing. Please fix these bugs (They may just be my computer) to help improve the playing experience for the League of Legends community.