"Back and forth membranes 
enfold: can reptilian
brain absorb it all?"

The folded membranes within in a cell create wonderful containers, like the walls of a canyon filled with water for swans to swim on. Or a soft bowl filled with straw where eggs can safely rest until they hatch. The human boy has to live not only with his neocortex and limbic system but the old reptilian complex itself. Sometimes there's a conflict between the rational child/adult and the old reptile within. Inside plant cells, thykaloid membranes are useful in storing chlorophyll. What would we do without membranes?