Basic Immunology Quiz

Immunology and the Immune System

• Immunity refers to the body's resistance against pathogens, toxins, or foreign substances.
• Immunology is the study of the immune system's components and functions, including responses to infections and diseases.

Types of Immunity

• Innate or Inborn Immunity
  • Present from birth, inherited from the mother via the placenta.
  • Nonspecific, does not require prior exposure to pathogens.
• Acquired or Adaptive Immunity
  • Not present from birth, developed throughout life through exposure to infections or vaccines.

Characteristics of Innate Immunity

• Acts immediately as a first line of defense against infectious agents.
• Non-specific defense mechanism, effective against a variety of microorganisms.
• Does not rely on previous pathogen contact.

Elements of Innate Immunity

• Anatomical Barriers: Skin and mucosal membranes provide initial defense.
• Cells: Include phagocytes and natural killer (NK) cells.
• Humoral Components: Include complement proteins and cytokines.

First Line of Defense: Skin

• Skin serves as a physical and chemical barrier against bacteria.
• The outer keratin layer, living epithelial cells, and skin thickness prevent bacterial penetration.
• Skin secretes acids (pyruvic and lactic acid) which create an acidic environment, inhibiting bacterial growth.
• Sebaceous glands produce bactericidal long-chain fatty acids.

Biomolecules of the Skin

• Antimicrobial Peptides (AMPs): Disrupt bacterial membranes and include families like defensins and cathelicidins.
• Produced by skin cells such as keratinocytes, fibroblasts, and macrophages.

pH of the Skin

• Maintains a pH of 5.4-5.9, creating an inhospitable environment for pathogens.

Myeloid Cells

• Skin-resident myeloid cells include Langerhans cells, macrophages, mast cells, and eosinophils, contributing to immune defense.

First Line of Defense: Respiratory Tract

• Nose hairs filter inhaled particles.
• Coughing and sneezing reflexes help expel foreign materials.
• The respiratory mucus layer traps inhaled microbes and contains antimicrobial substances.
• Cilia: Tiny, hair-like structures that move mucus to trap and expel pathogens before they enter the lungs.

First Line of Defense: Gastrointestinal Tract

• Human saliva exhibits antibacterial properties.
• The buccal cavity and large intestine harbor normal bacterial flora that can compete with pathogens.

Test your understanding of immunology and the immune system in this quiz. Explore key concepts such as immunity, the components of the immune system, and their functions. Perfect for those studying basic immunology.