Chapter 11 Flashcards
What are the differences between bacteria that reside in our bodies and those that cause disease?
Only normal in one part of your body
What is disease?
Any change from a general state of good health for an individual
Infection refers to:
An imbalance between the host and microbe
Mutualism
Both host and microbe benefit
Commensalism
The microbe benefits and the host is unaffected
What is a pathogen?
A microbe whose relationship with its host is parasitic and results in infection and disease
How does disease occur?
- An exogenous infection occurs if a pathogen enters sterile tissue
- An endogenous infection occurs if normal microbiota enter
- Primary infections occur in healthy bodies ex) flu
- Secondary infections occur in a body weakened by a primary infection ex) pneumonia
Portals of entry?
Mouth, GI, skin, urogenital
Disease progression as a microbe?
- Get in
- Attach
- Survive
- Damage
- Get out
What is it called when a microbe establishes itself in a host and causes damage?
Virulence
Disease progression in a human?
- Incubation - entry of microbe
- Prodromal - mild signs/symptoms
- Acute period -signs and symptoms are most intense
- Period of decline - signs and symptoms subside
- Period of convalescence - body back to normal
Acute diseases
Very short ex) flu
Chronic disease
Linger for long periods of time and slower to develop ex) hepatitis
What is invasiveness?
The ability of a pathogen to penetrate tissues and spread
What is virulence factors?
Any characteristic or structure of the microbe contributes to its ability to establish itself in the host and cause damage
Examples of virulence factors?
Streptokinase- dissolves fibrin clots and allows dissemination of the bacteria
Leukocidins-disintegrate neutrophils and macrophages (WBC)
Hemolysins-dissolves red blood cells
Biofilms- immune cells cannot reach bacterial cells covered in biofilm, protective structure
Two types of toxins:
- Exotoxins
2. Endotoxins
Exotoxins
Proteins that are secreted
Endotoxins
Released upon disintegration of bacteria
Chemical composition differential characteristics between exotoxins and endotoxins?
Exo: small particles
Endo: lipopolysaccaride of well wall