Blockchain is a disruptive technology with the potential to have a significant impact on business models and industries, similar to the adoption of Internet. Blockchain promotes distributed, open, inclusive, immutable, and secure architectural approaches, instead of centralized, hidden, exclusive, and alterable alternatives. The adoption of blockchain in the healthcare domain offers promising solutions for securing communications among stakeholders, efficient delivery of clinical reports, and integrating various kinds of private health records of individuals on a secure infrastructure. Accordingly, the main aim of this study is to propose a holistic blockchain structure covering all stakeholders in the healthcare domain and to analyse opportunities and challenges by presenting an integrated blockchain architecture. The comprehensive view of blockchain based healthcare system consists of services as follows: personal medical health record storage and access, personal genomic data storage and access, inventory tracking and buy-sell mechanism, health research commons, health document notary services, doctor services, digital health wallet, peer-to peer insurance. The opportunities of using blockchain in the healthcare domain are considered with respect to several viewpoints such as transparency, accountability, decentralization, record accuracy, secure transactions, interoperability, lower costs, collaboration, agility, individualized care with specialized treatment, improved diagnosis methods, risk of insurance contract, prevention of counterfeit drugs and improved quality of medical research. Challenges associated with the implementation of blockchain in the healthcare domain are also highlighted, such as governance, lack of legacy, privacy, sustainability, scalability, adoption of participation, and cost of operations.