Why do we roll to the right?

A number of students have asked me at different times why we roll to the right when coming up from the floor. My explanation has been somewhat incomplete as I only knew that it was an esoteric, symbolic gesture which had to do with the sun rising in the east. But mostly I just want students to all roll the same way so they don't roll uncomfortably into each other and keeping it on the right simplifies it. However a more thorough explanation is the following:
"It is considered, in India, more auspicious to enter a holy place with the right foot and in many parts of the world, we extend our right hand in greeting. The right side also represents the east: rolling towards the east or the rising sun symbolizes asking for blessings, grace and bliss.
Physiologically, since your heart is on the left, when you roll to the right it remains open and free of pressure. It also keeps one of the main channels of prana/life force active and helps keep your body in a state of calmness as you come into a sitting position."
-Desiree Rumbaugh.