ABSTRACT
The reduction of ontogeny and phylogeny to cell-cell communications mediated by soluble growth factors and their cognate receptors allowed for their superposition, mimicking a wave collapse in Quantum Mechanics, leading to the realization that life is primarily energy flow, not material traits. This is particularly true of embryogenesis, which tends to focus on the morphologic changes that occur over the course of development from the zygote to the offspring, when in fact when seen from the perspective of cell-cell communication. The subsequent discovery that PTHrP is produced by lung fibroblasts, stimulating lung surfactant synthesis by neighboring alveolar type 2 cells provided an explanation for ‘how and why’ it was needed for lung development.
