Lamellar bodies are groups of lipids and protein that are structurally similar to tubular myelin, but are found inside instead of outside the type II pneumocytes.  Similarly to its function in organizing tubular myelin, SP-B arranges lipids into the lamellar body structure. Basically, SP-B plays a role in the organogenesis (formation of structure) of lamellar bodies.  The lamellar bodies are then secreted into the fluid lining the interior of alveoli, and become tubular myelin.  This role is critical for making pulmonary surfactant (see below)