Exam 4 Flashcards
(28 cards)
What factors can cause disease?
• Physical agents
• Chemical agents
• Biological agents
• Nutritional factors
• Genetic factors
How do humans acquire normal microbiota and where are they found?
• Acquired during birth and early life
• Found in:
- Digestive tract
- Skin
- Respiratory tract
- Urogenital tract
What is the Human Microbiome Project?
A research initiative to analyze and understand the microorganisms that live in and on the human body
What are the benefits of normal microbiota?
• Aids in digestion
• Produces vitamins
• Prevents pathogen colonization
• Supports immune system development
How do opportunistic and true pathogens differ?
• Opportunistic: Only cause disease in weakened hosts
• True pathogens: Can cause disease in healthy hosts
What are the five steps of causing disease?
- Adhesion
- Invasion
- Multiplication
- Tissue damage
- Exit
How do pathogens enter the body?
Through natural openings and breaks in protective barriers
What are the portals of entry for pathogens?
• Respiratory tract
• Digestive tract
• Urogenital tract
• Skin breaks
• Mucous membranes
How do pathogens avoid phagocytosis?
• Capsule formation
• Enzyme production
• Toxin release
• Antigenic variation
What are three ways pathogens cause disease?
• Direct cell damage
• Toxin production
• Immune response triggering
What is an exoenzyme and what are examples?
Enzymes secreted by cells that break down substances outside the cell
Examples: proteases, lipases, hyaluronidase
How do exotoxins and endotoxins compare?
• Exotoxins: Secreted by living bacteria, highly specific
• Endotoxins: Released upon bacterial death, general symptoms
What are three ways of naming exotoxins?
• By target tissue
• By organism
• By mechanism of action
How do pathogens exit the body?
• Respiratory secretions
• Bodily fluids
• Skin lesions
• Fecal matter
What are examples of signs and symptoms?
• Fever
• Pain
• Inflammation
• Fatigue
• Specific disease symptoms
What are the 5 phases of infection?
- Incubation
- Prodromal
- Acute
- Decline
- Convalescence
How do reservoirs and sources of disease differ?
• Reservoir: Where pathogen normally lives
• Source: Immediate origin of infection
What are examples of disease reservoirs?
Living: humans, animals, plants
Non-living: soil, water, food
What are examples of disease transmission?
Direct: person-to-person contact
Indirect: through vectors or vehicles
What are 5 states of human carriers?
• Incubatory
• Convalescent
• Healthy
• Chronic
• Asymptomatic
How do biological and mechanical vectors differ?
• Biological: Pathogen multiplies in vector
• Mechanical: Vector simply transfers pathogen
Define communicable, contagious, and non-communicable diseases
• Communicable: Can be transmitted
• Contagious: Easily transmitted
• Non-communicable: Cannot be transmitted
What’s the difference between vehicles and fomites?
• Vehicle: Substance carrying pathogen
• Fomite: Inanimate object carrying pathogen
How do droplets, droplet nuclei, and aerosols compare?
• Droplets: Large particles that fall quickly
• Droplet nuclei: Dried residue that floats
• Aerosols: Small particles that remain airborne
