Answer Happy

Normal inspiration is caused by ________________ of the__________________ and theexternal intercostal muscles. This causesan _________________ in the intrathoraticvolume and therefore areduction in the intrathoracic ________________. The reductioninintrathoracic pressure creates a pressure gradient between theatmospheric air and the_____________ thus resulting in air movementinto the ______________. Expiration isbasically the reverse processof ________________, which occurs upon relaxation of theinspiratorymuscles due to the “elastic recoil” of the _____________ and______________.