Host-Microbe Interactions

Question 1

Large array of microorganisms that inhabit the human body in abundance.

Answer 1

Normal resident flora (biota)

Question 2

Plays a role in the body’s defense by producing antibodies and inhibiting entry and growth of other pathogens.

Answer 2

Normal Microflora

Question 3

Some pathogens can be found among the normal flora but generally don’t cause problems because ________ limits their growth.

Answer 3

competition

Question 4

Microbes are more prominent in locations exposed to the environment such as the:

Answer 4

skin and digestive tract

Question 5

Present for several days, weeks, or months and then disappear.

Answer 5

Transient microflora

Question 6

Uterus is normally _____ at birth, but microbes from the vagina can enter the womb and colonize the skin of the baby.

Answer 6

sterile

Question 7

Infant’s respiratory system colonization starts from:

Answer 7

first breath

Question 8

Infant’s intestine colonization starts from:

Answer 8

first breath

Question 9

Relationships Between Normal Biota and Host:

Answer 9

1. Microbial antagonism/competitive exclusion
2. Mutualism
3. Commensalism
4. Parasitism

Question 10

Both parties benefited.

Answer 10

Mutualism

Question 11

One benefits, the other is unaffected.

Answer 11

Commensalism

Question 12

One benefits, the other is harmed.

Answer 12

Parasitism

Question 13

Pathogens causing periodontal disease and gingivitis have been found to have receptors, not for the teeth, but for the oral streptococci that colonize the teeth.

Answer 13

Cooperation between microbes

Question 14

Changes in body function, e.g. pain and malaise (vague feeling of
body discomfort).

Answer 14

Symptoms

Question 15

Objective changes that the physician can observe and measure; e.g. fever, lesions.

Answer 15

Signs

Question 16

A specific group of symptoms accompanying certain signs.

Answer 16

Syndrome

Question 17

Infectious agent transferred from infected person to another, who also becomes infected; e.g. chickenpox, flu.

Answer 17

Communicable

Question 18

Very communicable diseases.

Answer 18

Contagious

Question 19

Cannot transfer from one person to another.

Answer 19

Non-communicable

Question 20

Number of people in a population who develop a disease during a particular time period.

Answer 20

Incidence

Question 21

Number of people in a population who develop a disease at a specified time.

Answer 21

Prevalence

Question 22

Occasionally occurring

Answer 22

Sporadic

Question 23

Constantly present in population, e.g. Common cold

Answer 23

Endemic

Question 24

Many people acquire disease in a very short time.

Answer 24

Epidemic

Question 25

Global scale

Answer 25

Pandemic

Question 26

Develops rapidly but lasts only a short while.

Answer 26

Acute

Question 27

Develops more slowly.

Answer 27

Chronic

Question 28

Between acute and chronic.

Answer 28

Subacute

Question 29

Causative agent is inactive for some time but then becomes active.

Answer 29

Latent

Question 30

Confined to a small area of the body, e.g. boils .

Answer 30

Local infection

Question 31

Spread by blood or lymph.

Answer 31

Systemic (generalized)

Question 32

Confined to a specific part, e.g. teeth, tonsils.

Answer 32

Focal

Question 33

Spread of microbes, especially bacteria or their toxins, from a focus of infection.

Answer 33

Sepsis

Question 34

Harbors a particular pathogen without manifesting any signs and symptoms.

Answer 34

Carrier

Question 35

Inoculating an infective agent.

Answer 35

Exposure

Question 36

Establishment of the infective agent in the host.

Answer 36

Infection

Question 37

Interval between the initial infection and the first appearance of any signs or symptoms.

Answer 37

Incubation

Question 38

Characterized by early, mild symptoms of disease, such as general aches and malaise.

Answer 38

Prodromal

Question 39

Disease is most severe; overt signs and symptoms.

Answer 39

Period of illness

Question 40

Signs and symptoms subside; patient is vulnerable to secondary infections.

Answer 40

Period of decline

Question 41

The person regains strength and the body returns to its pre-diseased state. Recovery has occurred.

Answer 41

Period of convalescence

Question 42

Reservoirs of Infection:

Answer 42

1. Human carriers 2. Animal reservoirs - zoonoses 3. Nonliving - soil and water 4. Vectors - mosquitoes

Question 43

Diseases that occur in wild animals and can be transmitted to humans, e.g. rabies and leptospirosis.

Answer 43

Zoonoses

Question 43

Transmissions of Infection:

Answer 43

1. Direct contact 2. Indirect contact - fomites (nonliving object involved in spread of infection: handkerchief) 3. Droplets - sneezing 4. Vehicle transmission - water, food or, air

Question 44

Studies when and where diseases occur and how they are transmitted in populations.

Answer 44

Epidemiology

Question 44

A microorganism’s potential to cause an infection or disease.

Answer 44

Pathogenicity

Question 45

Properties enabling a microbe to invade and infect a host.

Answer 45

Virulence factors

Question 45

Production of disease is a series of steps:

Answer 45

1. Transmission to a susceptible host 2. Adherence to appropriate target tissue 3. Invasion 4. Colonization 5. Damage to host while evading defenses 6. Exit from host 7. Survival before being transmitted to another host

Question 46

Ability of a microbe to cause infection that takes the presence or absence of virulence factors into account.

Answer 46

Virulence

Question 47

The route that a microbe takes to enter body tissues.

Answer 47

Portal of entry

Question 48

Enter the body from the outside environment; ex. common cold.

Answer 48

Exogenous agents

Question 48

Already exist in the body; ex. Candidiasis.

Answer 48

Endogenous agents

Question 49

It is also susceptible to infection.

Answer 49

Conjunctiva

Question 50

A large number of microbes enter through the:

Answer 50

mucus membranes

Question 51

It isn’t a normal portal of entry for microbes but may become a portal with individuals who practice anal sex.

Answer 51

Rectum

Question 52

Smaller microbes are more likely to enter through this portal.

Answer 52

Respiratory tract

Question 53

Agents of sexually transmitted diseases and urinary tract infections (UTI’s) enter here.

Answer 53

Urogenital tract

Question 54

Some agents enter directly through the skin (broken or unbroken); others enter via the:

Answer 54

urethral mucosa or vaginal lining

Question 55

Microbes gain a more stable position in the body.

Answer 55

Adhesion

Question 56

Bacteria often attach via:

Answer 56

1. fimbrae 2. flagella 3. pili 4. slime layers 5. capsules

Question 57

Viruses use to attach to a specific receptor on the cell surface.

Answer 57

Spikes

Question 58

They use their structures of locomotion to burrow into the host cell.

Answer 58

Protozoa

Question 59

Worms mechanically fasten using:

Answer 59

1. suckers 2. hooks 3. barbs

Question 60

Evading Host Defenses:

Answer 60

1. Enzymes 2. Antigenic variation 3. Host cytoskeleton penetration - production of invasins cell.

Question 61

Altering surface antigens; some bacteria have alternative genes (Neisseria gonorrhoae and Trypanosoma brucei).

Answer 61

Antigenic variation

Question 62

Often caused by a microbe’s virulence factors.

Answer 62

Tissue damage

Question 63

Directly inflict tissue damage. Breakdown a host’s defenses and allow the microbe to move deeper into the tissue.

Answer 63

Enzymes

Question 64

Digests keratin, a primary component of skin, hair, and nails.

Answer 64

Keratinase

Question 64

Digest the protective coating on mucus membranes.

Answer 64

Mucinase

Question 65

Digests the collagen fibers of connective tissue.

Answer 65

Collagenase

Question 66

Digests the component holding animal cells together.

Answer 66

Hyaluronidase

Question 67

Any chemical that is poisonous to another organism.

Answer 67

Toxin

Question 67

Released by living bacterial cells into infected tissue.

Answer 67

Exotoxin

Question 67

Released when the bacteria are damaged or destroyed.

Answer 67

Endotoxin

Question 67

Circulation of bacteria in the bloodstream.

Answer 67

Bacteremia

Question 68

Infection Types:

Answer 68

1. Localized infection 2. Mixed infection 3. Systemic infection 4. Focal infection

Question 69

Acute illness caused by bacteria or toxin in the blood (a.k.a blood poisoning).

Answer 69

Septicemia

Question 70

The agent remains localized but its toxins are spread throughout the body.

Answer 70

Toxemia

Question 71

Circulation of a virus in the blood.

Answer 71

Viremia

Question 72

Specific route taken by pathogens to leave the host. Often exit through the same portal of entry.

Answer 72

Portal of exit

Question 73

Most individuals shed billions of dead skin cells each day and it is the largest component of _________.

Answer 73

household dust

Question 74

Potential exit for the agents of fungal skin infections, syphilis, herpes simplex and smallpox.

Answer 74

Skin scales

Question 75

Common exit for intestinal pathogens and helminth worms (specifically eggs or larva).

Answer 75

Fecal exit

Question 76

It is also a location of neonatal infectious agents.

Answer 76

Vagina

Question 77

High acidity make is less common mode of exit but agents of typhoid fever and tuberculosis may exit in it.

Answer 77

Urine

Question 78

There is no natural exit for blood except:

Answer 78

menses

Question 79

Shared needles and small abrasions causes by intercourse can also result in the transmission of pathogens especially:

Answer 79

HIV and hepatitis