Injections and puncture wounds are examples of this portal of entry:

Injections and puncture wounds introduce pathogens directly into the body, bypassing the external barriers like the skin. This method is known as the parenteral route, which refers to any route that does not involve the gastrointestinal tract and typically includes entry points such as intravenous injections, intramuscular shots, and any kind of wound where skin integrity is compromised.

The skin, while a major barrier to infection, does not directly reference the mode of entry in this context but is rather the protective layer being breached. Therefore, recognizing injections and puncture wounds as parenteral illustrates how these methods introduce pathogens into the internal environment, which can lead to infection or disease if not properly managed. The parenteral tissue as a portal of entry encompasses both the specific physiological process occurring through injections and the concepts surrounding skin breaches, making the choice accurate in identifying the route of infection.