Infectious disease Part 1 Flashcards Preview

Pathophysiology II > Infectious disease Part 1 > Flashcards

Flashcards in Infectious disease Part 1 Deck (26):
1

Commensals

Microbial cells that help the body and rarely cause disease unless the balance is disrupted

2

Skin defenses

-defensins
-keratinized outer layer of hair, skin and nails
-low pH
-fatty acids (sebaceous glands + sweat glands)

3

Respiratory tract defenses

-bronchial epithelium and ciliary activity
-mucous layer
-defensins
-IgA
-alveolar macrophages

4

GI tract defenses

-gastric acid
-pancreatic enzymes
-bile detergents
-Peyer patches
-defensins
-peristalsis
-protective flora

5

Urogenital tract defenses

-frequent bladder flushing w/ urine
-low vaginal pH
-intact epidermal/epithelial barrier

6

Consequences of microbe infection depend on:

1. Virulence of the organism
2. Magnitude of the infection
3. Pattern of seeding
4. Host factors

7

Pathogens can be spread from person to person via:

-respiratory
-fecal-oral
-sexual routes

8

Stages of infection

1. Host encounter
2. Gain entry
3. Multiply and spread
4. Direct or indirect tissue injury

9

Outcomes of infection

1. Resolution
2. Chronic active infection
3. Prolonged asymptomatic excretion (asymptomatic carrier)
4. Latency of agent
5. Host death

10

Acute infection

3-4 weeks

11

Subacute infection

1-3 months

12

Chronic infection

>3 months

13

General ways that microbes evade host defenses

-antigenic variation
-resistance to antimicrobial peptides
-resistance to phagocytosis
-evasion of apoptosis
-resistance to cytokines, chemokine, and complement mediated host defenses
-evasion of recognition by CD4+ and CD8+ by coming up with a fake MHC complex

14

Tropism

The ability of a virus to only infect certain cells/organs

15

Mechanisms of viral injury to cells

-preventing synthesis of host DNAs, RNA, protein
-anti-viral immune response
-transformation of infected cells

16

Bacterial virulence

-damage to host tissues depends on the ability of the bacteria to adhere to host cells, invade cells/tissues, or deliver toxins
-virulence genes regulate these functions

17

Bacterial adherence to host cells

1. Adhesins = bacterial surface proteins that bind bacteria to host cells or CM
2. Pili- hair like filamentous proteins on the surface of bacteria that act like adhesins

18

Bacterial toxins

Any substance that contributes to illness. Can be an exotoxin or endotoxin

19

Endotoxin

A lipopolysaccharide in the outer membrane of gram negative bacteria that stimulates host immune responses and injures the host

20

Exotoxin

Produced inside gram positive bacteria as a part of their growth and metabolism. Secreted/released fatter lysis

21

How do exotoxins damage host cells?

-damage tissue integrity by enzymes digesting structural proteins
-cell dysfunction or death by altering intracellular signaling
-paralysis d/t neurotoxins blocking neurotransmitter release
-t cell proliferation and cytokine release (toxic shock syndrome) d/t superantigens stimulate large numbers of T cells

22

4 categories of viral infection

1. Acute/transient infections
2. Chronic productive infections
3. Chronic latent infections
4. Transforming infections

23

Acute infections

-Measles
-Mumps
-poliovirus
-viral hemorrhaguc fevers

24

Chronic productive infection

-HBV
-HIV

25

Chronic latent infections

-HSV
-VZV
-CMV

26

Transforming infection

EBV