Final answer:
The structures containing hydrolytic enzymes used by white blood cells to digest bacteria are called lysosomes. They function as part of the immune system, particularly in macrophages through phagocytosis.
Step-by-step explanation:
White blood cells that engulf and destroy bacteria in the human body are equipped with special structures that contain hydrolase enzymes, primarily for the digestion of the bacteria. These crucial structures are called lysosomes. Macrophages, a type of white blood cell involved in the immune response, utilize a process known as phagocytosis to ingest bacteria. During phagocytosis, a portion of the macrophage's plasma membrane envelops the bacterium, creating a vesicle. This vesicle then fuses with a lysosome, where hydrolytic enzymes within the lysosome digest the bacteria, thus destroying the pathogen.