What are the structures of Golgi apparatus?

Golgi apparatus consists of a system of flattened sacs called vesicles that are membrane-bound and filled with fluid. These vesicles are arranged parallel to one another in the form of stacks called cisternae. The smooth, flattened sacs of the cisternae are slightly bent and stacked in a semicircular arrangement. There are about 4 to 8 cisternae in each stack. Each group of cisternae is membrane bound so its internal components are kept separate from the cell’s cytoplasm.