Sun is the Cause - Moon is the Inner Effect(s) - Rising/Ascendant is Outer Effect(s)
Moon is the Inner Cause behind the Rising/Ascendant Outer Effect, though in itself is an immediate inner effect of the cause which always is The Sun
Ascendant is the Causal Factor behind all outward Manifestation and its Effects... the inner being stored at the Nadir or I.C. and the outer world at the M.C. or Mid-Heaven, marking the upper (MC and Houses 7-12) and lower hemispheres (IC and Houses 1-6).
Descendant makes the horizon and horizontal perspective where the lower and upper, inner and outer, meet in the present moment, here and now. The Ascendant (or Self) interacting with The Descendant (or Other) in the dance of life, fleeting and transitory yet rooted in Eternity (The Sun).
The Planets indicate this entire interaction and how it develops/unfolds in the evolution of an individual human persona (inner planets) as well as collectively in society (Jupiter-Saturn) and universally for all Humankind (Uranus-Neptune-Pluto).
The Nodes are the ultimate effects or karmic consequences of our causal actions and activity that inevitably breed effects:
Suffice to say, good Karma leads one to the insight, wisdom and inspiration of the forward flow (North Node) willing to embrace the unknown and take the high road... where taking a path of strong resistance leads one to a state of least resistance in the process of one's spiritual/human journey.
Negative Karma is clinging to old ways and habits, where one relies on the path of least resistance (i.e. the "comfort zone") and in doing so is inwardly creating more inner resistance to change, growth and living in the present, free of the past.
**More to come at a later time... to see further elaboration on this topic (overtime) visit http://cosmicexploration.blogspot.com