Meridians are a traditional Chinese terminology referring to energy channels. I visualise them as train stations and the Qi is the express train referring to the principal that vital energy travels through the body along the specific meridian pathways. This energy is designed to sustain and revitalise our bodies distributing even energy flow which nourishes the system from within the cellular level.
Blockages are metaphorically speaking the express train forced to make a temporary stop at a meridian station point which throws the whole timetable schedule into disarray. Much the same with the meridians in our body system. Releasing these blockages are paramount for a healthy even distribution of energy vital for the well being of the mind body and soul.