Immune System Function and Divisions

Immune System Function

• The immune system protects the body from infections caused by bacteria, viruses, fungi, and parasites.

Immune System Divisions

• The immune system is divided into two main branches: the innate (non-specific) immune system and the acquired (adaptive) immune system.

Innate Immune Response

• The innate immune response is the body's first line of defense against pathogens.
• It is non-specific, meaning it acts against all types of microorganisms.
• It includes the following components:
  • Mechanical Barriers: Intact skin and mucus membranes prevent pathogen entry.
  • Chemical Barriers: Substances like sweat, tears, and stomach acid (HCl) inhibit microbial growth.
  • Normal Bacterial Flora: Beneficial bacteria compete with pathogens for resources, space, and receptors, preventing colonization.
  • Non-specific Inflammatory Response: Characterized by vasodilation, cell aggregation, leading to symptoms like heat, redness, swelling (edema), and pain.
  • Cells of innate immunity: Phagocytic cells engulf and digest invading microorganisms.

Acquired Immune Response

• The acquired immune response is developed through previous exposure to specific pathogens.
• It provides targeted protection against specific microorganisms.