How do Transformers circulatory systems work in TFP? It appears that they have a heart. But inside their heart is their spark. Now why would their sparks be inside their beating hearts? Bulkhead stated that their lifeforce is composed of Energon. So I am wondering if their sparks are made out of Energon. Perhaps their sparks are in their hearts because Energon has to be pumped into their sparks constantly to replenish their energy? In other words, do their sparks lose energy regularly?