Subject to the provisions of this act, the board of county institutions shall operate the hospital or institution for the care and treatment of persons suffering from tuberculosis or any physical or mental ailment or impairment, including the condition of senility. The board of county institutions shall employ an executive head and such other employees as may be necessary to carry out the provisions of this act. The compensation and expenses necessary to the discharge of official duties of the executive head and employees and the number thereof shall be within the funds made available therefor. The board shall be responsible for the establishment of an annual budget and all charges and disbursements shall be within the budget so prepared and approved by the board of supervisors. The board shall be responsible for establishing the policies covering the operation of the hospital or institution, including the conditions of admission and the rates to be charged for the care of patients. The board of county institutions shall cooperate with all agencies and departments of the state, particularly the public health department, the mental health department and the department of social services.