Does a tick have a heart?

Insects do not have lungs, they breath through spiracles and trachea - small holes leading to small tubes that deliver oxygen directly to cells using diffusion. They don't have blood the way we do, that is, their internal fluid carries no oxygen to cells, it merely circulates nutrients, hormones, immune cells, etc. They have a rudimentary heart that just sloshes the fluid around in their open interior, there are no blood vessels. Their brain is just an enlarged ganglia and can store about as much information as one of the older computer chips. They have accessory ganglia that aid eating, walking, flying and reactions to stimuli so the brain doesn't have to do all the work. So, you're right, they are about 90% involuntary behavior and have only about 10% volition. you welcome~Trisha~