Prana is one, like the ocean, but named according to function and location.
Asana & Pranayama
Pranayama burns defects, modifies chakra tendencies. Respiratory benefits are secondary.
Breath and mind: two sides of the same coin. Breath assists comprehension.
Pranayama uses vehicle of the breath. Breath & mind must benefit from asana.
Asana + shvasayama (breath restraint)—prerequisite for pranayama & dhyana.