Immunity and Defense Mechanisms

Study Notes

Immunity and Defense Mechanisms

Natural Immunity is developed through exposure to infections.
- Natural Active Immunity is acquired from recovery after illness.
  - Example: Immunity to mumps after recovering from the illness.
- Natural Passive Immunity is short-term immunity passed from mother to child.
  - This occurs through colostrum and breastfeeding.
Artificial Immunity is developed through medical intervention.
- Artificial Active Immunity is acquired through vaccinations.
  - Example: Immunity to tetanus after receiving the tetanus vaccine.
- Artificial Passive Immunity is immunity received from an injection of antibodies.
  - Example: Immunity to diphtheria after receiving a booster injection.
Body's Natural Defenses include physical and chemical barriers.
- Physical Barriers: Skin, cilia, and mucus prevent pathogens from entering the body.
- Chemical Barriers: Lysozyme in tears and saliva, and sweat gland secretions inhibit microbial growth.
Inflammatory Response is characterized by redness, swelling, pain, and warmth.
- This serves to isolate and eliminate pathogens.
Lines of Defense are categorized into three stages.
- First Line: Skin, tears, and mucus act as external barriers.
- Second Line: Inflammatory response and non-specific immune cells.
- Third Line: Specific immune responses target particular pathogens, such as the production of antibodies.

Bacterial Characteristics and Environments

Pathogenic Bacteria cause diseases in humans.
- Pseudomonas aeruginosa is known for its blue-green pigment, pyocyanin, and is common in nosocomial infections.
- Clostridium species cause diseases under anaerobic (oxygen-free) conditions and are often found in soil and dust.
- Bacillus species are known for forming spores and are mostly found in dust, soil, and animal intestines.
Environmental Requirements influence bacterial growth and survival.
- Endospore Formation helps bacteria survive in harsh environments like soil or dust.
- Anaerobic Conditions are necessary for bacteria like Clostridium to grow, causing diseases in oxygen-deprived tissues.
Toxin Production plays a role in bacterial pathogenesis.
- Bacteria like Corynebacterium diphtheriae produce toxins, especially in low-iron environments, which lead to severe symptoms.

Transmission and Complications of Bacterial Infections

Disease Transmission occurs through various methods.
- Zoonotic Pathogens spread from animals to humans.
  - Examples include Francisella tularensis (tularemia) and Brucella abortus (brucellosis).
- Nosocomial Infections are acquired in healthcare settings.
  - Pseudomonas aeruginosa is a leading cause of these infections.
- Sexually Transmitted Diseases are spread through sexual contact.
  - Neisseria gonorrhoeae is an example and can lead to complications like pelvic inflammatory disease and infertility.
Complications arise from bacterial infections.
- Infections due to Antibiotic Use: Some bacteria, like Clostridium difficile, overgrow when normal gut flora is disrupted by antibiotics, leading to severe diarrhea.
- Inflammation and Infection Sites: Coccobacill infections like Vibrio cholerae lead to complications such as dehydration.

Natural Immunity

Developed through exposure to infections.
Natural Active Immunity: Acquired from recovery after an illness, for example, mumps.
Natural Passive Immunity: Short-term immunity passed from mother to child through colostrum and breastfeeding.

Artificial Immunity

Developed through medical intervention.
Artificial Active Immunity: Acquired through vaccinations, for example, the tetanus vaccine.
Artificial Passive Immunity: Immunity received from an injection of antibodies, for example, a diphtheria booster injection.

Body's Natural Defenses

Physical Barriers: Skin, cilia, and mucus act as barriers to prevent pathogens from entering the body.
Chemical Barriers: Lysozyme in tears and saliva, and sweat gland secretions help inhibit microbial growth.
Inflammatory Response: Redness, swelling, pain, and warmth, which serve to isolate and eliminate pathogens.

Lines of Defense

First Line: Skin, tears, mucus as external barriers.
Second Line: Inflammatory response and non-specific immune cells.
Third Line: Specific immune responses targeting particular pathogens (antibody production).

Description

Explore the complex world of immunity and the defense mechanisms our body employs to fight infections. This quiz covers both natural and artificial immunity types, including active and passive forms. Test your knowledge on how physical and chemical barriers protect us from pathogens.