Hi,
In the works of any entity (company, association, corporation, school, college, hospital, foundation, etc.), the Administration is in charge of organizing, decision-making, control, supervision, growth, and basically the overall performance and well-being of the entity.
Human Resources is only a branch or department of the entity. Its purpose revolves around the people that work for the entity—employees, laborers, administrators, and so on. Human Resources is in charge of supervising these people, assuring work environment quality (individual and collective), searching for new and efficient resources (new employees, so to speak), and everything else related while also remaining in accord with the Administration's requests/preferences/policies and with the law.
Monika