Here are some resources for teaching neural transmission. There’s a lesson plan with various activities and a slideshow to support it, along with an unlabelled diagram of a neuron and a set of sequencing cards for events that occur during the action potential. These have been prepared for students who are scared of science, so descriptions have been simplified and you might want to use them as a bridging resource to something more complete.
Here are a couple more GIFs I’ve been mucking around with whilst teaching neural transmission. Right click to save, or link to the URL if embedding in Google Slides.