Health diary

  ​Understanding the Human Immune System: Our Internal Shield ​The human immune system is a complex network designed to protect us from harmful invaders like bacteria, viruses, and parasites. It operates through two primary systems: Innate Immunity and Adaptive Immunity . Image by Pikisuperstar on Freepik 1. Innate Immunity: The First and Second Lines of Defense ​Innate immunity is non-specific, meaning it reacts the same way to every pathogen it encounters. It is composed of our first and second lines of defense. ​The First Line of Defense (Physical & Chemical Barriers) ​This is the body’s "border security," designed to prevent intruders from entering in the first place. ​ The Skin: The epidermis consists of epithelial cells that eventually die and shed off every 28 days. Sweat contains lysozyme , an enzyme that kills pathogens, while sebum (skin oil) keeps the skin moist and acidic to discourage bacterial growth. ​ Physical Traps: Tiny hairs in the nose and eyelashe...