Chapter 15 Flashcards
1
Q
host defence mechanisms
A
- ways in which the body protects itself from pathogens
- 3 lines of defence
2
Q
lines of defense
A
- first 2 are non specific
- third is specific, the immune response
3
Q
third line of defense
A
- antibodies are produced in response to antigens
- the immune system, lymphocytes
4
Q
second line of defence
A
cellular
- inflammation
- phagocytosis
- transferrin
- fever
- interferons
- complement system
- acute-phase proteins
- cytokines
5
Q
first line of defence
A
acellular
- intact skin
- mucous membranes
- cellular and chemical factors
- microbial antagonism
6
Q
non-specific host defence mechanisms
A
- general and serve to protect body against harmful substances
- innate or inborn resistance, mechanical and physical barriers, chemical factors, microbial antagonism, fever, inflammation, phagocytosis
7
Q
physical barriers
A
- skin and mucous membranes
8
Q
cellular and chemical factors
A
- pH, temperature, perspiration, cilia, and enzyme secretions
- components of first line
9
Q
microbial antagonism
A
- when indigenous microbiota prevent colonization of bacteria as a result of competition for sites and nutrients and production of lethal substances
10
Q
transferrin
A
- a glycoprotein
- levels increase in response to bacterial infection
- binds to iron to deprive pathogens of it
11
Q
fever
A
- stimulated by progenies substances like pathogens and interleukin 1 (IL1)
- increases hosts defences by stimulating leukocytes, reducing available iron, and inducing production of IL-1
12
Q
interferons
A
- small antiviral proteins produced by virus infected cells that prevent viruses form multiplying
- no virus specific but species specific
- can cause nonspecific flu like symptoms
13
Q
3 types of interferons
A
- alpha
- beta
- gamma
- they are induced by different stimuli like viruses, tutors, bacteria, and foreign cells
14
Q
the complement system
A
- group of 30 different proteins found in normal blood plasma
- assists in destruction of many different pathogens
- complementary to immune system
15
Q
complement cascade
A
when complement components interact with each other in a stepwise manner
16
Q
opsinization
A
- process where phagocytosis is facilitated by the deposition of options which are antibodies or complement fragments onto pathogens
- it labels the pathogen for phagocytosis
17
Q
acute-phase proteins
A
- plasma proteins that increase rapidly in response to infection, inflammation, or tissue injury
18
Q
cytokines
A
- chemical mediators released from body cells
- enable cells to communicate with each other within the immune system and between immune and other body systems
19
Q
chemoattractants
A
- type of cytokine called chemokines
- they recruit phagocytes to sites where they are needed
20
Q
inflammation
A
- when the body responds to any injury, irritation, microbial invasion, or bacterial toxin by a complex series of events
21
Q
3 major events of inflammation
A
1) capillary vasodilation to increase BF
2) increased permeability of capillaries for escape of plasma and plasma proteins
3) exit of leukocytes from capillaries and their accumulation at injury site
22
Q
primary purposes of inflammation
A
- localize infection
- prevent spread of microbial invaders
- neutralize toxins being produced at the site
- aid in repair of damaged tissue
23
Q
4 major signs and symptoms of inflammation
A
- redness
- heat
- edema
- pain
24
Q
what causes edema
A
plasma that escapes from the capillaries into the site
25
sequence of events in inflammation
1) tissue injury
2) vasodilation
3) increased permeability
4) emigration of leukocytes from blood vessel to tissue
5) chemotaxis
6) phagocytosis
26
inflammatory exudate
- the accumulation of fluid, cells, and cellular debris at the inflammation site
27
purulent exudate
- pus
| - thick and green-yellow exudate with many live and dead leukocytes
28
pyogenic microbes
- result in additional pus formation
| - staphylococci and streptococci
29
phagocytes
- phagocytic white blood cells
30
phagocytosis
- the process by which phagocytes surround and engulf foreign material
31
3 major leukocytes
- monocytes
- lymphocytes
- granulocytes (eosinophils, basophils, neutrophils)
32
macrophages
- phagocytosis
- stimulates rest of immune system to respond
- antigen presenting cell
33
neutrophils
- phagocytize
| - release toxin that kills surrounding tissue
34
most important groups of phagocytes in human body
- macrophages and neutrophils
35
4 steps in phagocytosis
1) chemotaxis
2) attachment
3) ingestion
4) digestion
36
chemotaxis
- phagocytes are attracted by chemotactic agents to site
37
attachment
phagocyte attaches to object
38
ingestion
pseudopodia surround object and it is taken into the cell
39
digestion
object is broken down and dissolved by digestive enzymes and other mechanisms
40
mechanisms by which pathogens escape phagocytosis
- capsules serve to protect organism
- some bacteria produce exoenzyme leukocidin which kills phagocyte
- some bacteria like M TB are not destroyed within phagolysosome
- mechanisms by which each pathogen evades digestion by lysosomal enzymes is different for each pathogen
41
disorders that affect immune resposne
- leukopenia
- disorders affecting leukocyte motility and chemotaxis (related to actin defect)
- disorder affecting intracellular killing by phagocytes (chronic granulomatous disease)
42
leukopenia
- abnormally low number to circulation leukocytes
43
other factors affecting immune response (8)
- nutritional status
- increased iron levels
- stress
- cancer and chemo
- genetic defects
- age
- AIDS
- drugs
