On the Three Lokas of the Lungs

 The three lokas of bhur, bhuvar and svar in all probability denote the three portions of the lung:

1. Bhu loka: the acinus, the productive portion of the lung

2. Bhuvar loka: the bronchiolar region, the region of the birds

3. Svar loka: the central axial, the bronchial region.