To investigate the physical conditions within the Broad Line Region (BLR) of Active Galactic Nuclei (AGN) we studied the spectral properties of a sample of 90 broad line emitting sources, collected at the Sloan Digital Sky Survey (SDSS) database. Taking into account the Balmer series of hydrogen emission lines, we analyzed the broad line components, from which we extracted several fiux and profile measurements. Our determinations were compared with other source physical properties, such as the continuum source mass, luminosity, and accretion rate, in order to test within our sample the reliability of some commonly invoked assumptions and their relation with the results of recent techniques, which are presently being used to explore the physics of AGN.