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Flashcards in lecture 6- host defence and immunity Deck (70):
1

resident biota

human body contains many habitants
-same body part can harbour different (but stable) communities at different times

2

Microbiota:

The community of microbes that lives in a specific part of the body
-bacteria, archaea, eukarya, VIRUSES

3

microbiome

The collection of organisms, their genomes and genes
-microbial ecosystem understood through genetics

4

Skin Microbiota

Acquisition: starts in birth canal and continues through environment (interaction c/ microbes is good - form immunity)

-Variety of Environments
-Acidic pH (pH 4-6)
-High in Salt, low water

Organisms:
Resident
-Staphylococcus app
Transient
-Propionibacterium acnes
Anaerobic
-Haemophillus spp.
-Mycobacterium spp.
-Bacillus spp. (usually from soil)
-Candida spp. (eukaryotic yeast)

5

The eye microbiota

acquisition: the environment
-harsh environment for bacteria d/t constant flushing and lysozyme in tears

-transient bacteria
Usually skin flora:
S. epidermidis
And
various diphtheroids

E. Coli
Klebsiella
Proteus

environmental contact c/ microbes cause Diseases:
S. pneuomoniae
H. Influenzae
Various virus’

6

microbiota: oral and nasal

Acquisition:
Birth canal, caregiver contact, Food, water, and fingers.

-protection:
Saliva, lysozyme
Cutaneous tissue
Immune surveillance

resident and transient microbes

Birth:
Neisseria spp. (non-pathogenic)
Streptococcus Spp.
Actinomyces Spp.
Lactobacillus Spp.

Teeth:
Prevotella
Fusobacterium
S. mutans
S. salivarius
(500+ sp.)

7

resident microbes

benefit host - help us do things

8

transient microbes

non-essential; may be pathogenic

9

why do dentists often administer antibiotics to its with a heart murmur?

S. aureus, S. epidermis are residents in mouth. Direct connection from mouth to heart c/ arteries and veins increase the change of these microbes getting into blood

-pt c/ murmur have pooling blood in heart where bacteria could grow

10

Microbiota: respiratory

unsure of acquisition
-all microbes are transient
-have "mucocilary escalator" to bring out foreign substance.

-Biolfilm formers:
S. pneumoniae
P. aeruginosa
H. influenzae
K. pneumoniae

11

what micro was responsible for cystic fibrosis

p. auruginosa

12

lower Gi tract anatomy consists of?

Stomach
Duodenum
Ileum
Jejunum
Colon
Ascending
Transverse
Descending
-7 different types of cells for absorption, protection, ect.
Environment is extremely diverse throughout the gi tract

13

microbiota: stomach

Acquisition: As a fetus, baby formula*, food & water, tasting their environment.
-protection: Acidic Environment (pH ~2-4)*

-resident and transient bacteria

-Helicobacter pylori and its role in gastritis and peptic ulcer disease was discovered by drinking bacteria, producing ulcer , treating it

V.cholerae (pathogenic) -- killed at pH 4 (if malnourished pH rises and this pathogen can cause disease)

14

culture independent method?

NGS

15

microbiota: the intestines

Duodenum (pH 8)
10 000 microbes

Jejunum (pH 8)
10^7 mm^3

Ileum & Colon (pH 5-7)
1011 / gram of faces

*over 1000 species

16

microbiota: urogenital

acquisition - surrounding external environment (usually comes in backwards - not through kidney)

protection: constant flushing

Transient (most)
Aerobic residents (some)

distal urethra:
S. epidermidis
Enterococcus spp.

17

Ecosystem

composed of communities (exchange c/ each other and their abiotic environment)
-stble ecosystems provide benefits (O2 production, water filtering, vitamin production)

18

meta-organism

human body
-co-evolved with specific communities of microbes: help us grow and develop

host-microbe interactions : -maintains community of commensals and symbionts
-helps prevent establishment and expansion of pathogens
-supports healthy function of metabolic processes

19

commensal organisms

-can be opportunistic but they only take / we supply them they don’t give anything back

20

symbionts

mutualistic relationship

21

how do microbiota differ between humans?

differs

22

why does the micro biome differ between body parts?

Particular niche requirements (ex: oxygen, pH, sugar, etc.)

Extracellular components that interact with receptors in host

23

explain the three basic steps of pathogen-human interaction

1. contact
2. infection
3. disease

24

infection

A condition in which pathogenic microbes penetrate host defences, enter tissues and multiply

25

infectious disease

disruption of tissue or organ (pathologic state) caused by microbes or their products

26

pathogen

Parasitic relationship with its host; results in infection and disease (in susceptible individuals)

27

what does type and severity of infection depend on (4)

1.Pathogenicity of the organism
2.Dose
3.Condition of the host
4.Portal of entry

28

pathogenicity

an organism’s potential to cause infection or disease

29

true pathogens

-lifestyle depends on infecting the host
-Attack healthy people
-Infection made worse by a weak or immature immune system

30

opportunistic pathogens

Only cause disease when given opportunity (decreased immunity)

31

what is the process of infection?

1. establishment
2. spread
3. disease effects

32

5 patters of infection

1.Localized
2. Systemic
3. Focal
4. Mixed
5. Primary - Secondary

33

necrosis

accumulated damage leads to cell death and tissue death

34

localized infection

-pathogens stay local to where it began
*most common

35

systemic infection

pathogens spread to multiple sites and tissues through blood stream (usually)

Ex) viral infections (HIV, chickenpox)

-Salmonella enterica serovar Typhi
-causes typhoid fever
-Invade intestinal epithelium, spreads to macrophage, can become resident in gall bladder

36

focal infection

infectious agent (toxin) leaves local infection and goes to other areas but pathogen stays local

ex) Streptococcal pharyngitis
Bacteria in throat (“Strep throat”)
-Antibodies against bacterial cell wall also attack other tissues, such as heart and joints

-ex) dental infection going to heart

37

mixed infection

-Multiple species contribute to infection

Example: dog bite
all sorts of different bacteria enter the wound

-Can be called “polymicrobial” disease

38

primary-secondary infection

-Successive

-Can occur due to weakened immunity

-Localized or systemic

Example:
Child scratches chickenpox (primary)
Then gets a localized Staphylococcus aureus infection (secondary)

-UTI eats to vaginal infection

39

sign

any objective evidence of disease as noted by an observer

40

symptom

the subjective evidence of disease as sensed by the patient

41

syndrome

when a disease can be identified or defined by a certain complex of signs and symptoms

42

Signs and Symptoms of infectious disease

signs: fever, septicemia, microbes in tissue fluids, chest sounds

symptoms: chills, pain, aches, soreness, irritation, malaise, fatigue

43

septicemia

microorganisms are multiplying in the blood and are present in large numbers

ex)meningitis – divides within 20 mins and can kill a pt within 24 hours

44

bacteremia

microbes are present in the blood but are not necessarily multiplying
*NO Signs of septicaemia - still dangerous

45

first line of defence

physical and chemical barriers - skin, cilia, mucous, secretions, resident microbiota

-Innate and nonspecific
-doesnt improve c/ exposure

46

second line of defence

inflammation, phagocytic white blood cells

-innate and non-specific
*communicate c/ third one defence

47

third line of defence

recognition of infectious agents (memory)
-B cells and T cells

Antibodies

-slower b/c has to be specific to pathogen --> develop this by experience and contact c/ microbes

*communicates c/ 2nd line

48

macrophage

immune cell
-eats foreign particles and displays on cell membrane
-asks T and B cells if they are foreign or not

49

how are the lungs nearly bacteria free if you breath in many microbes c/ each breath

first line of defence!
-Mucus, cilia, and macrophage

50

what are nonspecific chemical defences?

-Sebaceous secretions
-Lysozyme in tears (attacks bacterial cell wall)
-Lactic acid and electrolyte concentrations of sweat
-Skin’s acidic pH and fatty acid content
-HCl in the stomach
-Digestive juices and bile in the intestine
(break down membranes and denature proteins)
-Acidic pH in the vagina

51

3 components of innate immunity

1. Antimicrobial proteins
2. Antimicrobial peptides
3. White blood cells (leukocytes)

52

immunology

the study of all features of the body’s second and third lines of defense

53

what does healthy immune system do?

-Surveillance of the body
-Recognition of foreign material
-Destruction of foreign entities

54

auto-immune disease

immune system makes a mistake and attacks body itself

ex) MS --> (possibly viral)
-autoantibodies attack myelin sheath in brain

55

hoe do cells distinguish between self and foreign particles

2nd & 3rd line do this

-Evaluate cells by examining markers on their surfaces (proteins)

-body identifies cancerous cells as damaged "self" = foreign and they want to destruct

56

compliment system

26 blood proteins that work together to destroy bacteria and certain viruses
-1 protein activates 2 more --> chain reaction to destroy infection

57

antimicrobial peptides (defensins)

-composition
-function
-location

-composed of 18-45 amino acids (small)

-Made by neutrophils and epithelial cells

-Active against bacteria, fungus, and enveloped viruses --> poke holes into bacteria causing death

-located on fingertips, stomach, vagina, armpits, nose, ect.

58

antimicrobial proteins: cytokines

signal for help (tell cells to come help or cell to self destruct)

-secrete chemical signals
-mediate inflammation

59

Interferons

involved in fight against viruses, other microbes, in immune regulation and communication

-Bind to cell surfaces and induce changes in gene expression (making them undergo cell suicide)

-viruses that come out of dormant stage and begin to divide are often controlled by these cells

60

what types of white blood cells are most abundant in second line of defence?

Neutrophils: Phagocytize bacteria (engulf it)
-First to arrive during an immune response (attracted by cytokines)

Eosinophils: Attach and destroy eukaryotic pathogens
- little bags of degradative enzymes
-Associated with inflammation and allergies (see pollen, cat hair as foreign cause unnecessary inflammatory response)

61

neutrophils

WBC
-surface granules contain digestive enzymes
-First to arrive during an immune response (inflammation)
-Attracted to wound d/t citokines--> Move from blood to wound when adhesion molecules hit "STOP" light
Hunt for invaders --> engolf

62

how do WBC get from the blood to the site of infection

Diapedesis
-White blood cells have special ability to cross tissue barriers
-attracted by chemotaxis (cytokine immune signal)
-hit the "STOP" signal in blood then travel through tissue (diapedesis) following chemotaxis to site on infection

63

T cells

cell-mediated immunity
-monocytes that arise from thymus

64

B cells

antibody-mediated immunity
-monocytes that arise from bone marrow

-Macrophage presents antigen to B cells
-->reacts to it and produces antibodies specific to that antigen

65

Macrophages

mature monocytes
long lived and can multiply

Innate response
-Many specific and nonspecific phagocytic and killing functions
-Mop up infections (phagocytosis)
-Full of digestive enzymes

66

reticuloendothelial system

-Network of connective tissue fibers
-Provides a passageway within and between tissues and organs
-White blood cells move through these corridors

67

lymphatic system

Immune corridor
Parallels blood system
Dumps into veins near heart

68

what is a meta organism?

dynamic microorganism environments sometimes centimetres apart

69

what are the 4 sources of acquiring microbiota?

Birth canal
Food
Breathing
environmental contact

70

what three microbes are naturally present in gut?

Lactobacilli
Coliforms
Anaerobes