There are more but these three are the main constituents of opium. The green unripe seed pods of opium poppy have to be treated a certain way to get the opium latex that, when dried, yields crude opium. It's important to remember that this is also the poppy that provides us with poppy seeds used in baking. read more
You can blend them so long as it isn't breaking up the seeds. You just want to give them the best wash you possibly can, and blending is a good way to go with seeds that have stubborn alkaloids stuck to them hard. You are right though, you just want to stuff that's on the outside. read more