Foundation models, characterized by their large-scale pretraining on diverse datasets, represent a transformative paradigm in artificial intelligence (AI) applications for healthcare systems and analytics. These models, often based on transformer architectures, enable generalist capabilities that extend beyond narrow task-specific AI, facilitating integration into complex healthcare infrastructures. This review synthesizes recent literature on the architectural integration of foundation models into healthcare systems, emphasizing their role in enhancing clinical analytics, decision support, and operational efficiency while addressing critical oversight considerations, including ethical, regulatory, and safety frameworks.In healthcare systems, foundation models are increasingly deployed to process multimodal data streams, including electronic health records (EHRs), medical imaging, and real-time patient monitoring. Architectural integration involves embedding these models within hospital information systems, enabling seamless data ingestion, inference, and feedback loops. For instance, models like those adapted from large language models (LLMs) support natural language processing for EHR mining, predictive analytics for disease progression, and generative tasks for synthetic data augmentation. Oversight considerations are paramount, encompassing regulatory compliance, bias mitigation, and human-AI collaboration protocols to ensure patient safety and equity.The synthesis highlights key architectural patterns: federated learning for privacy-preserving model training, hybrid human-AI workflows for clinical decision-making, and adaptive systems for continuous model recalibration. Analytics applications span precision medicine, where foundation models integrate genomic and clinical data for personalized interventions, to population health management, optimizing resource allocation through predictive modeling. Ethical oversight includes checklists for AI deployment in low- and middle-income countries (LMICs), emphasizing equitable access and cultural adaptability.Challenges in integration include data interoperability, model interpretability, and scalability in resource-constrained settings. Regulatory imperatives call for validation frameworks and safety standards to govern the rollout of generative AI. This review provides an original systems-level framing, structuring the discourse around data-to-decision pipelines, governance overlays, and evaluative metrics for sustainable adoption.Ultimately, foundation models hold promise for closed-loop healthcare systems, where AI-driven insights inform interventions and feedback refines models iteratively. However, rigorous oversight is essential to balance innovation with accountability, ensuring these technologies augment rather than disrupt clinical workflows. By synthesizing high-impact publications, this narrative review offers integrative insights for researchers, clinicians, and policymakers navigating AI-enabled healthcare transformation.