Chapter 13 Flashcards
Pathologic State
Results when the infection damages or disrupts tissues and organs. “I don’t feel good”.
Infectious Disease
The disruption of a tissue or organ caused by microbes or their products. For example, food poisoning or ebola.
Resident Biota
Microbes on the human body that has a stable, non-pathogenic relationship with the human host.
Sites that harbor a known normal biota
Skin, respiratory tract, GI tract, outer opening of urethra, external genitalia, vagina, external ear canal, external eye including lids and conjunctiva.
Microbial Antagonism
Bacterial biota benefit the human host by preventing the overgrowth of harmful microorganisms.
Endogenous Infections
Caused by biota that are already present in the body. Example- biofilm.
Pathogen
A microbe whose relationship with its host is parasitic and results in infection and disease.
True Pathogen
Capable of causing disease in a healthy person. Associated with a specific, recognizable disease.
Opportunistic Pathogen
Causes disease when host defenses are compromised.
Pathogenicity
Concept that describes an organism’s potential to cause disease. Become established in body parts not natural to them.
Factors that weaken host defenses/ increase susceptibility to infection
Old age, extreme youth, genetic defects in immunity and acquired defects in immunity (AIDS), surgery and organ transplants, organic diseases including cancer, liver malfunction, and diabetes, chemotherapy/immunosuppressive drugs, physical and mental stress, other infections.
Virulence
Degree of pathogenicity determined by its ability to establish itself in the host and cause damage.
Virulence Factor
Any characteristic or structure of the microbe that contributes to its virulence including ability to produce toxin, fimbrae, capsule. Adaptations used to invade and establish itself in host tissues.
Exogenous
Microorganism originating from source outside of the body.
GI Tract as Portal of Entry
Pathogens in food, drink, and other ingested subasances adapted to survive digestive enzymes and pH changes. Best known agents are enteric bacteria.
Infectious Agents that enter the skin
Common portal of entry including nicks, abrasions, and punctures. Some create their own passageway using digestive enzymes or bites.
Respiratory Portal of Entry
Includes the greatest number of pathogens due to the fact that structures in the respiratory tract have a continuous mucous membrane covering. Smaller cells and particles are inhaled more deeply.
Urogenital Portal of Entry
STDs account for nearly 4% of infections world wide. Not all are stis, some caused by displaced organisms.
Pathogens that infect during pregnancy and birth
Some microbes cross the placenta with an 80% fatality rate for syphilis. Some infections occur prenatally when the child is contaminated by the birth canal.
Infectious Dose (ID)
Smaller infectious dose, greater virulence. Infection only proceeds if ID is present.
Subclinical Dose
Numbers below infectious dose that do not result in infection.
Adhesion
A way for microbes to gain foothold on host tissue. Mechanisms of attachment include fimbrae, surface protein, and adhesive slimes and capsules for bacteria. Spikes for viruses. Hooks, suckers, and barbs for parasites.
Phagocytes
White blood cells that engulf and destroy pathogens with enzymes and antimicrobial chemicals. Strongest immune response.
Antiphagocytic factors
Used by some aggressive pathogens to avoid phagocytes. Include extracellular surface layer and some can survive inside phagocytes after ingestion.
