State two reasons why the patient must have an empty bladder before the injection of contrast media for an IVU procedure. 

The function of the lacrimal apparatus is _______________________. 

_______ is when antibodies bind to and block specific sites on viruses or exotoxins, preventing antigens from binding to receptors. 

The process of reducing virulence is called _________________. 

Toxins and flagella are classified as __________________ antigens.

What is the main function of a cytokine?

Which of the following is NOT a way that normal microbiota help protect the body from pathogens?

____________________ are protein molecules released by host cells that inhibit the spread of viral infections. 

_______ is a substance which provokes a specific immune response. 

_______________________of complement activation acts in conjunction with the action of antibodies.