A PMHNP is being recruited to help implement an evidence-based collaborative care model for depression management within a large primary care practice that serves 15,000 patients. The practice currently identifies patients with depression through routine PHQ-9 screening but lacks systematic follow-up, and many patients with positive screens are lost to follow-up or receive inconsistent treatment. The practice leadership wants to adopt the model used in the IMPACT trial. The PMHNP is planning the key components of the collaborative care implementation. Which of the following best describes the essential elements of the collaborative care model?