2.7

Question 1

3 requirements for successful infection

Answer 1

sufficient number of infectious virus particles
target cells must be susceptible, permissive, and accessible
local anti viral defenses must be absent or quiescent for awhile

Question 2

susceptible cell

Answer 2

has receptor

Question 3

permissive cell

Answer 3

has gene products to complete infectious cycle

Question 4

target cells must … (3)

Answer 4

accessible, susceptible and permissive

Question 5

incubation period

Answer 5

the time in which the infection does not have symptoms

Question 6

disease period

Answer 6

the time that the infection causes symptoms

Question 7

4 layers of immunity

Answer 7

physical barriers
antimicrobial proteins/intrinsic
innate immunity
adaptive immunity

Question 8

physical barriers listed (3)

Answer 8

epithelial cells
cilia
body temperature

Question 9

chemical barriers listed

Answer 9

mucus
acidic pH

Question 10

defenses to infection (4)

Answer 10

physical barriers
chemical barriers
soluble antimicrobials
microbiota

Question 11

whats the most common route of viral infections

Answer 11

inhalation

Question 12

what helps remove debris trapped in mucus

Answer 12

cilia

Question 13

what happens in the muscle, liver, spleen, and blood vessels? what are they classified as?

Answer 13

viruses replicate to increase their numbers here. they are considered secondary amplification sites before secondary viremia

Question 14

skin or target tissues? what happens there?

Answer 14

skin, lung, kidney, stomach, brain. they are the final target sites where the virus causes diseased symptoms

Question 15

order of entry and dissemination

Answer 15

1. reproduction at the site of entry
2. primary viremia
3. reproduction sites (secondary amplification sites, spleen, liver)
4. secondary viremia
5. reproduction sites/target tissues (skin, lung, stomach)

Question 16

secondary viremia

Answer 16

a higher level of virus in the blood after amplification in secondary target organs

Question 17

how do viruses spread through the host

Answer 17

through the bloodstream and lymphatic system

Question 18

3 things that could happen to viruses taken up by phagocytic macrophages or dendritic cells

Answer 18

inactivated
replicated
delivered to other tissues

Question 19

ways that a virus can pass through vascular epethial in different ways (3)

Answer 19

Infect endothelial cells
Transcytosis
Via inflammation or vascular damage

Question 20

how does a virus infect a sensory neuron

Answer 20

through the skin and infects sensory nerve endings. then it goes all the way up the axon and remains latent in the dorsal root ganglion.

Question 21

retrograde

Answer 21

from nerve ending to spinal cord

Question 22

antiretrograde

Answer 22

from spinal cord to nerve endings

Question 23

virus that can spread between neurons

Answer 23

herpes, rabies

Question 24

can neuron infections spread to liver or brain

Answer 24

yes but its very rare

Question 25

where do disseminated infections happen

Answer 25

bloodstream (free in plasma) lymphatic system (cell associated in lymphocytes)

Question 26

what delivers the virus to the target tissue

Answer 26

secondary viremia

Question 27

viral transmission to a new host normally occurs through what

Answer 27

body fluids

Question 28

apoptosis

Answer 28

programmed cell death

Question 29

is there inflammation for apoptosis

Answer 29

no

Question 30

is there inflammation for programmed necrosis

Answer 30

yes

Question 31

why doesn't apoptosis cause inflammation

Answer 31

the plasma membrane stays in tact so PAMPs/DAMPs dont spill out of it (silent death)

Question 32

autophagy is induced by what

Answer 32

stresses (starvation, viral infection)

Question 33

what does autophagy restrict

Answer 33

viral replication

Question 34

how does autophagy restrict viral replication

Answer 34

targets viruses to lysosomal pathways for degredation

Question 35

can viral proteins promote autophagy

Answer 35

yes

Question 36

whats an intrinsic defense

Answer 36

target the genome and inhibits replication

Question 37

epigenetic silencing

Answer 37

condensed chromatin when DNA enters the nucleus

Question 38

intrinsic defences (4)

Answer 38

apoptosis necroptosis autophagy epigenetic silencing

Question 39

where does primary replication occur

Answer 39

In the tissue/ epithelial cell (first place in the body where a virus replicates after entering the host)

Question 40

hope does the host respond (3)

Answer 40

IFN antibodies T cells