Morphine codeine and heroin are all opiates that function by what?

Morphine, codeine, and heroin are all opiates that function by binding to opioid receptors in the brain and spinal cord. This binding inhibits the transmission of pain signals and alters the perception of pain, leading to pain relief and euphoria. Additionally, these substances can affect other systems, resulting in side effects such as sedation and respiratory depression. Their addictive properties arise from their ability to stimulate the brain's reward pathways.