Overview of the Immune System

Overview of the Immune System

• The immune system's main function is to combat microbial pathogens by differentiating between self and non-self.
• It aims to eliminate microbial threats while avoiding attacks on the body's own cells.

Immune Response

• Immune responses vary based on the type of pathogen, which includes extracellular organisms (like bacteria, fungi, parasites) and intracellular pathogens (viruses).
• The immune system is comprised of innate and adaptive components that work collaboratively for a comprehensive defense.

Innate Immunity

• Innate immunity serves as the body's immediate, non-specific defense mechanism against pathogens.
• This system functions without prior exposure to the pathogens, offering rapid protection.

Components of Innate Immunity

• Physical Barriers: Includes skin and mucous membranes that serve as the first line of defense against pathogen entry.
• Chemical Barriers: Involves substances such as stomach acid and enzymes in saliva that neutralize and destroy harmful microorganisms.
• Cellular Defenses: Consists of white blood cells (e.g., macrophages, neutrophils, dendritic cells) responsible for engulfing and destroying invading organisms.
• Complement System: A collection of proteins in the blood that can lyse infected cells, recruit more immune cells, and enhance the process of phagocytosis.
• Inflammatory Response: A vital process for recruiting immune cells to sites of infection and facilitating tissue repair.
• Fever: Increased body temperature that boosts metabolic activity and enhances immune defenses.

Recognition Systems

• Pattern Recognition Receptors (PRRs): These receptors are located on immune cells and recognize specific structures on pathogens (PAMPs) or signs of damage from host cells (DAMPs).
• Important types of PRRs include:
  • Toll-like Receptors (TLRs)
  • NOD-like Receptors (NLRs)
  • C-type Lectin Receptors (CLRs)

Mechanisms of Innate Immunity

• Inflammation helps to isolate and eliminate pathogens.
• Phagocytosis involves immune cells engulfing and destroying invading organisms.
• The complement system aids in the opsonization and clearance of pathogens from the body.

This quiz covers the fundamentals of the immune system, including its role in identifying and combating various microbial pathogens. It delves into the mechanisms that differentiate between self and non-self entities, highlighting the intricate responses tailored to different types of organisms.