_Removal of mesenchyme halts branching
_Non lung mesenchyme does not support branching
_Lung mesenchyme placed in trachea or salivary gland induces specific
branching
_Proximal vs distal mesenchyme induces site appropriate epithelial cell
development
_Mesenchymal
factors are diffusable across membranes – No contact needed, but
gradients are very local.
_Epithelial factors �crosstalk� to determine mesenchymal growth and differentiation.