Various embodiments of the present invention are directed to limiting a presence of air bubbles in a fluidic medium expelled from a reservoir. In various embodiments, a reservoir is shaped so as to limit a presence of air bubbles in a fluidic medium expelled from the reservoir. Also, in various embodiments, a plunger head within a reservoir is shaped so as to limit a presence of air bubbles in a fluidic medium expelled from the reservoir. In some embodiments, both a reservoir and a plunger head within the reservoir are shaped so as to limit a presence of air bubbles in a fluidic medium expelled from the reservoir.