Аннотация:Simulated OCT signals from plain blood samples of thicknesses from 0.05 to 1 mm were obtained implementing Monte Carlo technique. Contributions of least- and multiple scattering, diffusive and non-diffusive fractions to the parts of the signal before the rear border peak, to the peak and behind it were estimated. It was show that least scattering and non-diffusive component prevail in the signal at optical depths smaller than 0.2 and 0.3 mm correspondingly. At larger depths multiple scattering and diffuse component prevail in the signal what may limit localization and detection of scattering objects at these depths. The distributions of contributing to the signal photons over scattering orders were analyzed. It was shown, that these dependences exhibit two maxima related to the borders of the investigated layer due to high anisotropy of the medium.