To function correctly, a healthy immune system must adhere to four essential principles:
: An overreaction to harmless environmental substances.
: Distinguishing the host's own cells ("self") from foreign elements ("non-self"). Immunology
The immune system is generally categorized into two interconnected systems: innate and adaptive immunity.
: Where the system mistakenly attacks "self" tissues. To function correctly, a healthy immune system must
: Retaining information from previous infections to prevent future illness.
: The ability to identify and fight off foreign infections. To function correctly
: 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.