Conducting research in the field of respiratory function, by using measuring and testing, has many purposes. First of all, it could show us how lungs function as a whole, but also, it could lead us to the exact location of a disorder. The aim of this paper is to, by employing accurate correlation of the measured variables of the flow/volume and flow/pressure curves, determine the location of the obstruction process in the tracheobronchial tree, in central-upper airways, as well as in a segment of small airways, so called 'silent zones' of the lungs, smaller than 2 mm in internal diameter. This research included 115 healthy people and 106 patients with chronic obstructive lungs disease, of both genders. The following values of the measured lungs' function parameters were found among healthy people (% of predicted value): FVC- 93%; FEV - 91,1 %; 1 FEV x 100/ FVC- 98,7%; MEF - 107,9%; MEF - 87,5%; MEF-98,9%; Rt-147,1%; ITGV-103,3%; SRt- 130,7%. 1 25%FVC 50%FVC Among the patients with chronic obstructive bronchitis, the following results of the examined parameters were gained: FVC- 66,3%; FEV - 54,2%; FEV x 100/ FVC- 80,7%; MEF - 19,3%; MEF - 23,1%; MEF- 40,5%; Rt- 51,2%; 1 1 25%FVC 50%FVC ITGV- 162,1%; SRt- 36,2%. Finally, there was a certain number of the healthy examinees who showed that direct indicators of the air flow resistance (Rt, SRt) were not significantly changed, while indirect indicators of the respiratory tracts obstruction (MEF , MEF ) were reduced, comparing to the expected tabular results.