Second line of defence Flashcards

1
Q

when does the second line of defenece operate

A

when a pathogen has crossed the first line of defence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what cells does the second line of defence involve

A

leukocytes - neutrophils, eosinophils, mast cells, macrophages, dendritic cells, natural killer cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the cells that are phagocytes

A

dendritic cells, macrophages and neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what do macrophages do

A

consume and destroy forgein or dead material by engulfing it via endocytosis, have lysosomes contains lysozymes which destroy the forgein/dead material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

aside from functioning as phagocytes, macrophages and dendritic cells are also

A

antigen presenting cells, they contain MHC II markers, on which they present antigens from the consumed material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where are neutrophils found and how do they compare to other phagocytes

A

most common type of WBC, found in the blood stream and pus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

where are monocytes found and how do they compare to other phagocytes

A

travels through the blood where it eventually migrates into the tissues of the body, here it specialises into macrophage, largest WBC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

where are macrophages found and how do they compare to other phagocytes

A

found everywhere inside the body, aside from function as a phagocyte and antigen presenting cell, they also produce a wide range of chemicals, enzymes, complememnt proteins and regulatory factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

where are dendritic cells found and how do they compare to other phagocytes

A

found on the surface of body (skin, eyes, mucous membranes), similar to macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

function of natural killer cells

A

upon finding a self cell displaying non-self antigens on its surface, NK cells release a death lignand - a siggnally molecule that stimulates the cell to die by apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

when is a natural killer cell activated

A

recruited to the sight of infection when infected cells release a cytokine callde interferon, kills cancerous cells or cells infected by a virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

structure of natural killer cell

A

large granulated cells conatining the killer inhibitory receptor and killer activation receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

killer inhibitory receptor

A

examines the surface for MHCI markers, prevents NK cell from killing healthy cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

killer activation reeceptor

A

binds to certain molecules which appear on ce;;s underhoing cellular stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where do mast cells reside

A

in connective tissue, such as under the skin and the connective tissue surrounding blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the process/function of mast cells

A

when an injury is detected or stimulated by antigens or allergens, they become activated and degranulate, releasing histamines

17
Q

histamines

A

molecules that induce an inflammatory response

18
Q

allergens

A

a type of antigen that produces an abnormally vigorous immune response to fight off a percieved pathogen

19
Q

what type of pathogen do eosinophils combat

A

effective in eliminating multicellular pathogens, secreted when there are skin conditions, allergic reations, autoimmune diseases, certain cancers and bone marrow disorders

20
Q

what is the function/process of eosinophils

A

flock to the site of infection, degranulate - secreting histamines and toxic cell mediators, perforating cell mediators and destroying pathogens, not phagocytees so dont engulf

21
Q

what are the two components of the second line of defence

A

cellular and non-cellular componenent

22
Q

two componenets of the non-cellular component of the second line

A

the complement system and cytokines

23
Q

cytokines

A

tiny proteins secreted by cells as a wway to communicate with one another

24
Q

interferons

A

type of cytokine that interfere with processes (e.g. viral replication)

25
when/what are interferons released from
cells infected by a virus
26
what do intereferons do
alert nearby cepps to reduce their susceptability to infection/heighten their antivirus defencees, promote activation of immune cells, differentitation of immune cells, increase body temp, recruit NK cells, upregulate the production of MHC I markers
27
where do complement proteins proteins reside
synthesised in the liver and ciirculate in the blood in ann inactive state, is activated when it is cleaved (part of it breaks free)
28
what are the three outcomes of complement
opsonization, chemotaxis, lysis
29
opsonization
process by which pathogens are coated with molecules so that they are more easily detected by phagocytes
30
chemotaxis
the complement proteins gather near the pathogen and attrcact phagocytes to it, making it easier to be destroyed
31
lysis
complement proteins join together on the surface of pathogens, forming a membrane attack complex (MAC), which creates pores in their membrane destroying the pathogen