Purchasing or Procurement Department

For credit unions $1 billion or more, can you please provide information of the following?

• Do you have a purchasing or procurement department? 
• If so, where does it fall in the organizational chart?
• How people staff are in the department?
• What are it's responsibilities? 

• If you don't have such a department, where does the responsibility for Vendor Management lie? and who has ultimate responsibility?

Thank you for your assistance!  :)