: Retaining information from previous infections to prevent future illness.
: An overreaction to harmless environmental substances. Immunology
: Distinguishing the host's own cells ("self") from foreign elements ("non-self"). : Retaining information from previous infections to prevent
: As the body’s first line of defense, the Innate Immune System is non-specific and immediate. It includes physical barriers like the skin and mucous membranes, as well as specialized cells like neutrophils and macrophages that engulf and destroy invaders through a process called phagocytosis. : As the body’s first line of defense,
: Where the system mistakenly attacks "self" tissues.
Immunology is the branch of biomedical science that explores the complex network of cells, tissues, and organs that constitute the immune system. Its primary function is to protect the host from pathogens such as bacteria, viruses, and parasites while maintaining a delicate balance of "self-recognition" to avoid attacking the body's own tissues. This essay explores the fundamental principles of immunity, the distinction between its two primary arms, and the importance of this field in modern medicine. 1. The Two Arms of the Immune System
