How does marijuana? Smoked cannabis can quickly reach the bloodstream and brain. There cannabinoids binds to specific receptors, which are abundant in brain areas associated with memory, cognitive and motor coordination. The effects are dose dependent, past experiences, consumer expectations, the environment, the different sensitivities and personalities who consumes it, the way of preparation and route of administration (fastest when smoked). An experienced marijuana user can control and regulate the dose needed to achieve the desired effects and avoid the undesirable effects of marijuana, although variations occur even in ideal conditions for study and control.