What is the term for the natural defense mechanisms present from birth?

The term for the natural defense mechanisms present from birth is innate immunity. Innate immunity refers to the body's first line of defense against pathogens, which includes physical barriers like the skin and mucus membranes, as well as immune responses that are immediate and non-specific. This type of immunity is present at birth and does not require prior exposure to any specific pathogens to be effective.

Innate immunity is crucial because it provides rapid responses to infections, utilizing various cells and processes, such as phagocytes that can engulf and destroy invaders, inflammatory responses, and the release of antimicrobial substances. This sets the stage for more specific immune responses that can develop later, which are characteristics of acquired immunity.

Active immunity and passive immunity refer to other forms of immune protection that involve either the individual's own immune response based on exposure to pathogens (active) or the transfer of antibodies from another source (passive). Acquired immunity, on the other hand, refers to responses that develop after exposure to antigens from pathogens or vaccinations. Therefore, while these terms relate to components of the immune system, innate immunity specifically describes the inherent defenses that are always ready at birth.