Patient Care Technician (PCT) AAH Practice Exam

Histamine plays a crucial role in the body's immune response, particularly in the context of inflammatory reactions. When the immune system detects a potential threat, such as an allergen or pathogen, histamine is released from mast cells and basophils. This release causes various physiological changes, including the dilation of blood vessels and increased permeability of capillaries. These changes lead to the classic signs of inflammation, such as redness, swelling, heat, and pain, which are essential for the body to fight off infections and heal wounds.

The other options reflect processes that histamine is not primarily responsible for. For example, preventing infection involves a range of immune responses beyond the scope of histamine's function. Facilitating oxygen transport is mainly the role of hemoglobin in red blood cells rather than histamine. Regulating blood sugar involves hormones like insulin and glucagon, making it unrelated to the actions of histamine. Thus, the role of histamine is most accurately captured by its function in triggering and mediating inflammatory responses.