Anatomy and Physiology II Practice Test

The type of immunity obtained through the injection of a vaccine is known as artificial active immunity. This immunity occurs when a person is exposed to a weakened or inactivated form of a pathogen, which stimulates the immune system to produce its own antibodies. Vaccines mimic an infection without causing the disease, allowing the immune system to recognize and remember the pathogen in case of future exposure.

In this scenario, the individual’s immune system actively responds by creating specific defensive mechanisms, including memory cells, which provide long-lasting protection. This is distinct from other types of immunity. For example, natural active immunity results from exposure to pathogens in the environment, leading to natural infection and immune response. Natural passive immunity involves the transfer of antibodies from mother to infant, such as through breast milk, providing temporary protection without activation of the infant's immune response. Lastly, artificial passive immunity is gained through direct injection of antibodies, which offers immediate but short-term protection as the immune system is not activated to produce its own antibodies.