**6. Conclusions**

In this article, we have reviewed and compiled the optical properties of human tissues and the circulatory system with the main focus on blood. From this literature review, one of the main conclusions is that there are numerous factors of physical and methodological origin that are responsible for the study of the optical properties that anyone should aware of before performing own optical properties measurements. We have pointed out the main factors that influence absorption spectra of whole blood and hence influence optical properties. Revision of available polarimetric techniques can be helpful for the reader in the practice of biomedical optics. From this, we hope that we have provided the reader with a set of optical property spectra for whole blood and different polarimetric techniques that can be used in the practice of biomedical optics.

**Author Contributions:** The authors S.B. conceived the presented idea. S.B. developed the formulation or evolution of overarching research goals and aims. and performed the computations. Following co-authors (M.N., F.M., F.F., E.F.) encouraged first author to investigate a specific aspect and supervised the findings of this work. All authors provided critical feedback and helped in equal contribution to the formation of the research article. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
