Final answer:
Structures that allow pathogens to leave a diseased individual are called portals of exit, which include skin, respiratory, urogenital, and gastrointestinal tracts.
Step-by-step explanation:
Structures of the body that allow pathogens to leave a diseased individual are called portals of exit. These are anatomical features through which pathogens can leave to infect a new host. The most common portals of exit include the skin and the respiratory, urogenital, and gastrointestinal tracts. For example, coughing and sneezing can expel pathogens from the respiratory tract, while secretions and excretions like feces, urine, semen, vaginal secretions, tears, sweat, and shed skin cells can be vehicles for pathogens to exit the body. Similarly, pathogens that require insect vectors for transmission may leave the body in the blood during a bite.