The first part of an ETL process involves extracting the data from the source system(s). In many cases this represents the most important aspect of ETL, since extracting data correctly sets the stage for the success of subsequent processes.
The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In mammals, it exists distinctly only in the embryonic heart (where it is found between the two venae cavae); in nonmammalian chordates, however, the sinus venosus persists in the adult.n the adult, it is incorporated into the wall of the right atrium to form a smooth part called the sinus venarum, also known as the venarum sinus, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis. The sinus venosus also forms the SA node and the coronary sinus.
Sinusitis is a bacterial infection or inflammation of one or more of the sinus passages located in the bones surrounding the eyes and nose. It could be caused by a cold, flu, tonsillitis, allergies or poor mouth hygiene.