Chapter 14 Flashcards Preview

Uncategorized > Chapter 14 > Flashcards

Flashcards in Chapter 14 Deck (82)
1

pathology - also etiology & pathogenesis

scientific study of disease, including etiology (cause), pathogenesis (way a disease develops) and the structural and functional changes and their effects on the body caused by the disease.

2

etiology

the cause of a disease

3

pathogenesis

the way a disease develops

4

pathogen

disease-causing microorganism

5

infection

invasion and growth of pathogens in the body causing signs of illness, inflammation, and tissue damage

6

colonization

the presence and growth of microorganisms WITHOUT signs or symptoms

7

disease

abnormal state in which body is not performing its normal functions

8

normal microbiota/flora & locations

microorganisms that reside permanently in or on the body but do not cause disease under normal conditions.

LOCATIONS include skin, eyes, nose/throat, mouth, large intestine, urinary and reproductive systems

9

Normal microbiota: Skin

sweat & oil glands
keratin
moisture content

Most microbes don't become residents because secretions from sweat & oil glands have antimicrobial properties.

Keratin is also a resistant barrier, and low pH of skin inhibits many microbes.

Also, skin has a relatively low moisture content.

10

Normal microbiota: Eyes

conjunctiva
tears/blinking

Conjunctiva is the continuation of the skin or mucous membrane, contains the same microbiota found on skin.

Tears and blinking eliminate some microbes or inhibit others from colonizing.

11

Normal microbiota: Nose/throat

microbial antagonism
nasal secretion
mucus/ciliary action

Although some normal microbiota are potential pathogens, their ability to cause disease is reduced by microbial antagonism.

Nasal secretions kill or inhibit many microbes, and mucus and ciliary action remove many microbes.

12

Normal microbiota: Mouth

Moisture, warmth, presence of food
biting, chewing, tongue movements, salivary flow
saliva

Moisture, warmth, and constant presence of food make the mouth an ideal environment that supports very large and diverse microbial populations on the tongue, cheeks, teeth and gums.

Biting, chewing, tongue movements, and salivary flow dislodge microbes.

Saliva contains several antimicrobial substances

13

Normal microbiota: Large intestine

largest
mucus/shedding
mucosa
diarrhea

contains largest # of resident microbiota in the body b/c of available moisture and nutrients.

Mucus & periodic shedding of the lining prevent many microbes from attaching to the lining of the gastrointestinal tract, and mucosa produces several antimicrobial chemicals.

Diarrhea also flushes out some of the normal microbiota.

14

Normal microbiota: Urinary and Reproductive systems

urethra
vag
mucus/shedding
cilia/mucus

Lower urethra in both sexes has resident population.

Vag has its acid-tolerant population of microbes b/c of the nature of its secretions.

Mucus and periodic shedding of the lining prevent microbes from attaching to the lining; urine flow mechanically removes microbes, and pH of urin and urea are antimicrobial.

Cilia and mucus expel microbes from cervix into the vag, and acidity of the vag inhibits or kills microbes.

15

transient microbiota

microorganisms that are present in or on the body for a period of time and then disappear

16

microbial antagonism/competitive exclusion

CCSS

by competing for resources and/or producing bacteriocins, the normal microbiota protect the host by preventing the colonization and overgrowth of harmful microorganisms.

Includes Candida albicans, Salmonella, Shigella, Clostridium difficile

17

Microbial antagonism: Candida albicans

normal bacterial microbiota of the human vag is ~pH=4.

Presence of the normal bacterial microbiota inhibits growth of Candida albicans, which grows when balance between normal microbiota and pathogens is upset, and when pH is altered.

If population is eliminated by antibiotics, excessive douching, or deodorants, pH of vag reverts to neutral and C. albicans can flourish and become dominant microorganism there, which leads to vaginitis.

18

Microbial antagonism: E. coli

Produces bacteriocins (inhibits growth of other bacteria of same or related species such as pathogenic Salmonella and Shigella).

19

Microbial antagonism: Clostridium difficile

Normal microbiota of the large intestine effectively inhibit C. difficile, but if normal microbiota is eliminated (antibiotics), C. difficile can be a problem.

This microbe is responsible for nearly all gastrointestinal infections that follow antibiotic therapy, from mild diarrhea to sever or even fatal colitis (inflammation of colon).

20

Symbiosis

relationship between 2 organisms in which at least 1 organism is dependent on the other, such as the normal microbiota and the host.

Includes commensalism, mutualism, parasitism

21

Symbiosis: commensalism

one of the organisms BENEFITS, the other is unaffected.

EX: S. epidermidis on the surface of the skin (only bacteria benefits)

22

Symbiosis: mutualism

both organisms BENEFIT.

EX: E. coli in the large intestine.

23

Symbiosis: parasitism

one organism benefits at the expense of the other (many disease causing bacterias)

24

Opportunistic pathogens

Do not cause disease in their normal habitat in a healthy person; may cause disease IF it gains access to other sites of the body, IF the host is weakened, IF they are present in large #s

25

List Koch's postulates

Demonstrate a specific pathogenic microorganism is the cause of a specific disease.

1. pathogen must be present in every case of the disease.
2. pathogen must be isolated from the disease host and grown in pure culture.
3. the cultured pathogen must cause the disease when inoculated into a healthy, susceptible host.
4. same pathogen must be isolated from the inoculated host.

26

symptom

changes in body function; not apparent to an observer

27

signs

objective changes the physical can observe and measure

28

syndrome

specific group of symptoms and signs accompany a particular disease

29

communicable disease

disease that spreads from one host to another, directly or indirectly

30

contagious diseases

disease that easily spreads from one person to another.

31

noncommunicable disease

ex

disease that does not spread from one host to another: it is caused by one's own microbiota (pnemonias), or when external microorganisms are introduced into the body (Clostridium tetani)

32

incidence

#
common
probability

1. number of NEW cases of a disease in a population during a particular time period;
2. indicates how common a disease occurs during the time period;
3. indicator of a person's probability of developing the disease during the time period

33

prevalence

#
proportion
impact of disease on a population
probability of having the disease

1. the TOTAL number of cases of a disease in a population at a specific time (either time point or time period);

2. represents the proportion of population with the disease;

3. useful for assessing the impact of a disease on a population and a person's probability of having a disease.

34

sporadic disease

occurs occasionally;

ex: typhoid fever in the US

35

endemic disease

constantly present in a population; ex: common cold

36

epidemic disease

many people in a given area get it in a relatively short period of time;

ex: influenza

37

pandemic disease

epidemic disease that occurs worldwide

38

acute disease

develops rapidly but does not last

39

chronic disease

develops slowly and may last or recur for a long time

40

subacute disease

intermediate between acute and chronic diseases

41

latent disease

disease that the pathogen remains inactive for a period of time before becoming active

42

herd immunity

when the majority of a population have immunity against an infectious disease, the chance of the nonimmunized individuals to contract the disease is little: "community immunity"

43

local infection

invading microorganism are limited to a small area of the body

44

systemic infection

microorganism or their products are spread throughout the body by the blood or lymph

45

focal infection

infection originated from a local infection, later the pathogen or its products spread from local infection area to the other parts of the body

46

sepsis

toxic inflammatory condition arising from the spread of microbes

47

septicemia

blood poisoning, systemic infection arising from multiplication of pathogens in the blood; common example of sepsis.

48

bacteremia

presence of bacteria in the blood

49

toxemia

presence of toxins in the blood

50

viremia

presence of viruses in the blood

51

primary infection

acute infection that causes the initial illness

52

secondary infection

caused by opportunistic pathogen after primary infection has weakened the body's defenses

53

subclinical (inapparent) infection

inapparent infection; does not cause any noticible disease

54

5 sequential stages of infectious diseases

IPIDC -->

incubation period,
predromal period,
period of illness,
period of decline,
period of convalescence.

Patient can be infectious during every stage; infections can be spread even during incubation and convalescence.

55

incubation period

interval btw initial infection and first appearance of signs or symptoms

56

prodromal period

short period following the incubation period in some diseases; not all diseases have it; early, mild symptoms of disease, such as aches and malaise

57

period of illness

most severe stage; apparent signs and symptoms of disease; usually when a patient goes to a physician; immune system has not fully responded to pathogens; WBCs may increase/decreases; treatments and patient's defense end of the period of illness, or patient dies during this period

58

period of decline

signs and symptoms subside; immune response and products of imune response peak in this stage

59

period of convalescence

tissues repaired; patient regains strength and recovers

60

reservoir of infection

sites, living or nonliving, where pathogens are maintained as a continual source of illness. 3 types: Human, animal and nonliving

61

Human reservoir

HUMAN: people with signs and symptoms or carriers (show no sign of illness);

62

Animal reservoir

ANIMAL: zoonoses are diseases transmitted from animals to humans;

63

Nonliving reservoir

NONLIVING: soil, water, foods

64

3 principle routes of disease transmission; examples

contact, vehicle, vector

65

direct contact transmission; examples

person-to-person physical contact; touching, kissing, sex.

Common diseases: cold, flu, staph infections, hep A, measles, STDs

66

indirect contact transmission; examples

mediated through a nonliving object called a fomite.

Examples: tissues, handkerchiefs, towels, bedding, diapers, drinking cups, eating utensils, toys, money, thermometers. AIDS, hep B, tetanus

67

droplet transmission; examples

Microbes in droplet nuclei (mucus droplets) discharged through coughing, sneezing, talking, etc.

Travels <1 meter.

Examples: cold, flu, pneumonia, pertussis (whooping cough)

68

waterborne; examples

spread by water contaminated with untreated/poorly treated sewage.

EX: cholera

69

foodborne; examples

transmitted in foods incompletely cooked, poorly refrigerated, or prepared under unsanitary conditions.

EX: food poisoning, tapeworm manifestation

70

airborne; examples

spread of agents of infection by droplet nuclei in dust that travel > 1 meter from reservoir to host.

EX: measles, tuberculosis

71

vector transmission; examples

animals that transmit diseases from one host to another. - mechanical or biological transmission

72

mechanical transmission; examples

passively carries the pathogens such as on insect's feet or other body parts. Generally not a host for the multiplication of the pathogen (vs biological transmission)

EX: housefly can transfer pathogens of typhoid fever and bacillary dysentery (shigellosis) from feces of infected people to food

73

biological transmission; examples

transmit pathogens and serves as host for the multiplication of pathogens.

EX: arthropod bites infected person or animal and ingests infected blood. Pathogen reproduces in vector, increasing the number of pathogens which increases possibility that it will be transmitted to another host.

74

nosomial infection

infection acquired in hospital, nursing home, health care facilities.

Does not show any evidence of being present or incubating at the time of admission to a hospital; it is acquired as a result of the hospital stay. Important to wash your hands.

Nosocomial infections generally result from:
microorgs in the hospital environment,
compromised/weakened status of host,
and chain of transmission in the hospital.

75

emerging infectious disease

new or changing, showing an increase in incidence recently or potentially in the near future.

75% of EIDs are zoonotic, viral, and vector-borne

76

epidemiology

3 investigators SSN
3 types of investigation DAE

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

3 investigators: John Snow, Ignas Semmelweis, Florence Nightingale.

3 types of investigation: descriptive, analytical, experimental

77

descriptive epidemiology

collect all data that describe occurrence of the disease

78

analytical epidemiology

analyze a particular disease to determine its probable cause, mode of transmission, and possible means of prevention

79

experimental epidemiology

test a hypothesis concerning the cause of a disease

80

morbidity

incidence of specific notifiable diseases

81

mortality

number of deaths from these diseases

82

notifiable infectious disease

diseases for which physicians are required by law to report cases to the US public health svc