The Immune System Quiz

Study Notes

Provides resistance against microorganisms, including bacteria, fungi, and viruses.

Surface Barriers
- Acts as the first line of defense.
- Comprises intact skin and mucosal surfaces, designed to prevent pathogen entry.
Innate Internal Defenses
- Serves as the second line of defense.
- Activated when pathogens breach surface barriers.
- Employs inflammation and utilizes antimicrobial proteins and phagocytes to control the spread of invaders.
Adaptive (Specific) Defense System
- Functions as the third line of defense.
- Targets specific pathogens identified as threats.
- Involves a more prolonged response compared to innate defenses, ensuring a tailored attack against known enemies.

Helps assess patients by understanding healthy immune responses.
Provides resistance to disease-causing microorganisms like bacteria, fungi, and viruses.

First Line of Defense (Surface Barriers)
- Consists of intact skin and mucosae, serving as structural barriers.
Second Line of Defense (Innate Internal Defenses)
- Activated when surface barriers are breached.
- Involves inflammation and internal defenses such as antimicrobial proteins and phagocytes.
Third Line of Defense (Adaptive Defense System)
- Specialized response targeting identified pathogens.
- Response time is significantly longer than innate defenses.

Both systems work concurrently, utilizing common defensive molecules.
Innate responses have specific pathways for targeting foreign substances.
Proteins from innate responses can alert adaptive system cells to specific foreign molecules.

Surface barriers and innate internal defenses are operational from birth.
Adaptive immune system strengthens defenses when innate responses are insufficient.
Innate defenses lessen the burden on the adaptive system.

Components
- Skin: Heavily keratinized epidermis effective against microbes.
- Mucous Membranes: Provide mechanical barriers along bodily tracts.
Protective Chemicals
- Acid Mantle: Low pH secretions inhibit bacterial growth.
- Enzymes:
  - Lysozyme in saliva and respiratory mucus destroys microbes.
  - Stomach enzymes kill pathogens present in food.
- Mucin: Sticky substance traps pathogens in digestive and respiratory tracts.
- Defensins: Antimicrobial peptides released in response to breaches and inflammation.
- Other Chemicals:
  - Lipids in sebum and dermcidin in sweat are toxic to bacteria.