  We investigate the scaling relations of bulge and disk structural parameters
for a sample of 108 disk galaxies.Structural parameters are obtained from 2D
bulge/disk decomposition of H-band images.Bulges are modelled with a
generalized exponential (Sersic) with variable shape index n. We find that
bulge effective scalelength and luminosity increase with increasing n, but disk
properties are independent of bulge shape. As Hubble type T increases, bulges
become less luminous and their mean effective surface brightness gets fainter;
disks shows a similar, but much weaker, trend. When bulge parameters are
compared with disk ones, they are tightly correlated for n=1 bulges. The
correlations gradually worsen with increasing n such that n=4 bulges appear
virtually independent of their disks. The Kormendy relation, surf. brightness
vs. effect. radius, is shown to depend on bulge shape; the two parameters are
tightly correlated in n=4 bulges, and increasingly less so as n decreases;
disks are well correlated .Bulge-to-disk size ratios are independent of Hubble
type, but smaller for exponential bulges. Strongly barred SB galaxies with
exponential bulges are more luminous than their unbarred counterparts.
Exponential bulges appear to be closely related to their underlying disks,
while bulges with higher n values are less so. We interpret our results as
being most consistent with a secular evolutionary scenario, in which
dissipative processes in the disk are responsible for building up the bulges in
most spirals.
