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lecture 6- host defence and immunity Flashcards

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1
Q

resident biota

A

human body contains many habitants

-same body part can harbour different (but stable) communities at different times

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2
Q

Microbiota:

A

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

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3
Q

microbiome

A

The collection of organisms, their genomes and genes

-microbial ecosystem understood through genetics

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4
Q

Skin Microbiota

A

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)
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5
Q

The eye microbiota

A

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’

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6
Q

microbiota: oral and nasal

A

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.)
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7
Q

resident microbes

A

benefit host - help us do things

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8
Q

transient microbes

A

non-essential; may be pathogenic

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9
Q

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

A

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

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10
Q

Microbiota: respiratory

A

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
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11
Q

what micro was responsible for cystic fibrosis

A

p. auruginosa

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12
Q

lower Gi tract anatomy consists of?

A 
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
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13
Q

microbiota: stomach

A

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)

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14
Q

culture independent method?

A

NGS

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15
Q

microbiota: the intestines

A

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

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16
Q

microbiota: urogenital

A

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.

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17
Q

Ecosystem

A

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

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18
Q

meta-organism

A

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
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19
Q

commensal organisms

A

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

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20
Q

symbionts

A

mutualistic relationship

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21
Q

how do microbiota differ between humans?

A

differs

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22
Q

why does the micro biome differ between body parts?

A

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

Extracellular components that interact with receptors in host

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23
Q

explain the three basic steps of pathogen-human interaction

A
  1. contact
  2. infection
  3. disease
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24
Q

infection

A

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

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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

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