Poison arrow room

I have made it the room where you shoot the poison arrows. By the time I figured out what to do I had already used up my 2 arrows. How do I get more arrows? I tried leaving the pyramid and reentering. The arrows are still gone.

There are more wooden arrows in another room on the same level. It's in a small round jar to the right of the entrance into the room. It seems you can pick up an unlimited number of arrows from that jar.