Immunity is a fundamental part of the human body's defense system, protecting it from diseases and infections caused by bacteria, viruses, and fungi. Immunity is divided into two main types: innate immunity and acquired immunity, each with its own characteristics and mechanisms for defending the body. First: Innate Immunity This type of immunity is present from birth and is considered the first line of defense against any microbe that enters the body. Its characteristics: It is present from birth. It responds quickly to any pathogen. It is nonspecific, meaning it does not distinguish between different types of microbes. It does not leave long-term immunological memory. Its mechanisms of action: Physical barriers: such as the skin and mucous membranes, which prevent the entry of microbes. Defensive fluids: such as tears and saliva, which contain enzymes that kill germs. Defensive cells: such as phagocytes, which engulf and destroy microbes. The inflammatory response: which produces chemicals that increase blood flow and the flow of immune cells to the site of infection. Second: Adaptive Immunity This is the immunity the body acquires after exposure to a specific pathogen or after vaccination. Characteristics: It develops after exposure to the microbe or after receiving a vaccine. It is specific to each type of microbe. It has a long immunological memory, making the body more prepared to face the same microbe in the future. It is slower to respond compared to natural immunity upon initial exposure. Mechanisms of Action: T cells: These cells directly attack infected cells and help activate other immune cells. B cells: These cells produce antibodies that recognize and destroy microbes. Antibodies: These are special proteins that bind to antigens on the surface of microbes to destroy them or prevent their spread. The Relationship Between the Two Types of Immunity: Natural immunity acts as a rapid first line of defense to prevent the spread of infection. Adaptive immunity enhances the defense and provides long-term protection against diseases. Natural and acquired immunity complement each other. The former provides immediate and nonspecific protection, while the latter offers long-term and specific protection against diseases the body has previously encountered. Therefore, maintaining a healthy immune system is vital for human health. Al-Mustaqbal University is the university in Iraq
  الهدف 3 : الصحة الجيدة والرفاه