Question about part of the frog?

So for our class we are dissecting a frog and we need to write about it and I am about to write about the frog's mouth and internal organs but I forget what the glottis does? Does anyone know? I know it is the flap of tissue in the back of the frog's throat that acts like a trapdoor, but does it like ensure that the frogs won't choke on the food or something? I forget. If anyone remembers from their science class or just happens to know, please tell me what the glottis is for. Best answer 10 points, include thorough detail! Thanks!