Exam 3

Question 1

Definition of colonization

Answer 1

The act of taking up long-term residence; as in microbes establishing a steady relationship with a host.

Question 2

Definition of infection

Answer 2

a condition where the microbes get past host defenses, enter tissues, and multiply

Question 3

Definition of disease

Answer 3

deviation from health that results when cumulative effects on infection damage or disrupt tissues and organs

Question 4

What are the sites where normal biota is found in humans

Answer 4

skin and adjacent mucous membranes, upper respiratory tract, gastrointestinal tract(including mouth), outer portion or urethra, external genitalia, vagina, external ear canal, external eye(lids, conjuctiva)

Question 5

What is the difference between pathogenicity and virulence

Answer 5

• pathogenicity: an organisms potential to cause disease
• virulence: relative severity of a disease caused by a particular microbe(degree of pathogenicity)

Question 6

What’s the difference between endogenous and exogenous

Answer 6

• endogenous: organisms coming from somewhere in the same human host
• exogenous: organisms coming from outside the body

Question 7

What are the steps involved when a microbe causes disease in a host

Answer 7

1.) Finding a portal of entry: skin, GI tract, respiratory tract, urogenital tract, endogenous bacteria
2.) Attaching Firmly and Negotiating the Microbiome: fimbriae, capsules, surface proteins, viral spikes
3.) Surviving Host Defenses: avoiding phagocytosis, avoiding death inside phagocyte, absence of adaptive immunity
4.) Causing Damage: direct damage via enzymes or toxins, inducing excessive host response, causing epigenetic changes in host chromosome
5.) Exiting Host: respiratory tract, salivary glands, skin cells, fecal matter, urogenital tract, blood

Question 8

Define infectious dose

Answer 8

the minimum number of microbes necessary to cause infection to proceed: microorganisms with smaller infectious doses have greater virulence

Question 9

What are the ways in which microorganisms attach to the host

Answer 9

1.) bacterial, fungal, and protozoal: fimbriae(pili), surface proteins, adhesive slimes or capsules
2.) viruses: specialized receptors
3.) parasitic worms: suckers, hooks, and barbs

Question 10

What is the most potent endotoxin and which bacteria possess it

Answer 10

lipopolysaccharide(LPS); gram negative

Question 11

What are some differences between exotoxins and endotoxins

Answer 11

1.) Exotoxins are toxic in small amounts and endotoxins are in high doses
2.) Exotoxins involve small proteins and no fever, endotoxins involve lipopolysaccharide and has fever

Question 12

Definition of virulence factors

Answer 12

adaptations a microbe uses to establish itself in a host

Question 13

What is a localized infection

Answer 13

microbes enter the body, remain confined to a specific tissue

Question 14

What is a systemic infection

Answer 14

infection spreads to several sites and tissue fluids, usually by bloodstream but possibly by CSF and nerves

Question 15

What is a focal infection

Answer 15

Infectious agents spreads from a (usually asymptomatic) local site and is carried to other tissues

Question 16

What is a mixed/polymicrobial infection

Answer 16

several agents establish themselves simultaneously at the infection site

Question 17

What is the primary infection

Answer 17

the initial infection

Question 18

What is the secondary infection

Answer 18

A second infection caused by a different microbe, which complicates a primary infection; often a result of a lowered host immune defense

Question 19

What is an acute infection

Answer 19

infection comes on rapidly, with severe but short lives effects

Question 20

What is a chronic infection

Answer 20

infection that progresses and persists over a long period of time

Question 21

Define a sign, symptom. and syndrome

Answer 21

1.) Sign: objective evidence of disease as noted by an observer(temp, white spots on throat, crackling in chest)
2.) Symptom: subjective evidence of a disease as sensed by the patient(hot, sore throat)
3.) Syndrome: a disease identified by a certain complex signs and symptoms

Question 22

What is a sequelae and what is strep throats sequelae

Answer 22

long-term or permanent damage to tissues or organs caused by infectious disease; rheumatic heart disease and acute glomerulonephritis

Question 23

What are the stages of the course of infection and their definition

Answer 23

1.) Incubation period: the time from initial contact with infectious agent to the appearance of symptoms
2.) Prodromal stage: earliest noticeable symptoms of infection appear; vague feeling of discomfort
3.) Acute phase: infectious agent multiplies at high levels; greatest virulence; marked by fever and other prominent specific signs and symptoms
4.) Convalescent period: patient begins to respond to the infection and symptoms decline
5.) Continuation phase: only some infections have this phase; either organism lingers for months or organism is gone but symptoms continue

Question 24

Define healthcare associated infections

Answer 24

infectious diseases acquired or developed during a hospital or health care facility stay

Question 25

Summarize the three lines of host defense

Answer 25

1.) First Line: a surface protection composed of anatomical and physiological barriers that keep microbes from penetrating sterile body compartments 2.) Second Line: A cellular and chemical system that comes immediately into play if infectious agents make it past the surface defenses 3.) Third Line: Includes specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells

Question 26

Define marker or antigen

Answer 26

Consist of proteins or sugars that allow cells of the immune system to identify whether a newly discovered cell poses a threat and should be marked for destruction

Question 27

What are cytokines and what do they do

Answer 27

hundreds of small active molecules secreted to regulate, stimulate, suppress, and otherwise control many aspects of cell development, inflammation, and immunity: important for cell communcation

Question 28

What is one pro-inflammatory and one anti-inflammatory cytokine

Answer 28

Pro: interleukin 1 Anti: interleukin 10

Question 29

What are the four kinds of cells that function as phagocytes

Answer 29

- neutrophils - macrophages - dendritic cells - monocytes

Question 30

What are the three components of the first line of defense

Answer 30

- skin - mucous membranes - nonspecific chemical defenses

Question 31

Describe two examples of how the normal microbiota contribute to the first line of defense

Answer 31

1.) can block the access of pathogens to epithelial surfaces 2.) creates an unfavorable environment for pathogens by competing for limited nutrients and by altering the local pH

Question 32

What are the four major categories of the second line of defense

Answer 32

1.) phagocytosis 2.) inflammation 3.) fever 4.) antimicrobial proteins

Question 33

What does phagocytosis involve

Answer 33

eat bacteria and kill them through granules; called through chemotaxis

Question 34

What are the ways microbes acquire antimicrobial resistance

Answer 34

1.) spontaneous mutations in critical chromosomal genes 2.) acquisition of entire new genes or sets of genes via horizontal transfer from another species(plasmids) 3.) slowing or stopping of metabolism so that the microbe cannot be harmed by the antibiotic(biofilms)

Question 35

List the 5 cellular or structural mechanisms that microbes used to resist antimicrobials

Answer 35

1.) New enzymes are synthesized inactivating the drug 2.) Permeability or uptake of the drug into bacterium is deceased 3.) Drug is immediately eliminated 4.) Binding sites for drugs are decreased in number or affinity 5.) An affected metabolic pathway is shut down or an alternative pathway is used

Question 36

List the stages of inflammation

Answer 36

1.) Injury/Immediate reactions 2.) Vascular reactions 3.) Edema and pus formation 4.) Resolution/scar formation

Question 37

Discuss the mechanism of fever and how it helps defend the body

Answer 37

the fever inhibits multiplication of temperature-sensitive microorganisms & increases metabolism and stimulates immune reactions

Question 38

List the 4 functions of complement

Answer 38

1.) Produces MAC complex 2.) Produces anti-filmic 3,) produces chemotactic factors 4.) obsinine