<Tr> <Th> Artery </Th> <Td> Bronchial artery </Td> </Tr> <Tr> <Th> Vein </Th> <Td> Bronchial vein </Td> </Tr> <Tr> <Th> Nerve </Th> <Td> Pulmonary branches of vagus nerve </Td> </Tr> <Tr> <Th_colspan="2"> Identifiers </Th> </Tr>

What is the difference between primary and secondary bronchi