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Micro > lecture 6- host defence and immunity > Flashcards

lecture 6- host defence and immunity Flashcards

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
Q

infectious disease

A

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

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26
Q

pathogen

A

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

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27
Q

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

A
  1. Pathogenicity of the organism
  2. Dose
  3. Condition of the host
  4. Portal of entry
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28
Q

pathogenicity

A

an organism’s potential to cause infection or disease

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29
Q

true pathogens

A
  • lifestyle depends on infecting the host
  • Attack healthy people
  • Infection made worse by a weak or immature immune system
30
Q

opportunistic pathogens

A

Only cause disease when given opportunity (decreased immunity)

31
Q

what is the process of infection?

A
  1. establishment
  2. spread
  3. disease effects
32
Q

5 patters of infection

A
  1. Localized
  2. Systemic
  3. Focal
  4. Mixed
  5. Primary - Secondary
33
Q

necrosis

A

accumulated damage leads to cell death and tissue death

34
Q

localized infection

A
  • pathogens stay local to where it began

* most common

35
Q

systemic infection

A

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
Q

focal infection

A

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
Q

mixed infection

A

-Multiple species contribute to infection

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

-Can be called “polymicrobial” disease

38
Q

primary-secondary infection

A
  • 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
Q

sign

A

any objective evidence of disease as noted by an observer

40
Q

symptom

A

the subjective evidence of disease as sensed by the patient

41
Q

syndrome

A

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

42
Q

Signs and Symptoms of infectious disease

A

signs: fever, septicemia, microbes in tissue fluids, chest sounds
symptoms: chills, pain, aches, soreness, irritation, malaise, fatigue

43
Q

septicemia

A

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
Q

bacteremia

A

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

45
Q

first line of defence

A

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

  • Innate and nonspecific
  • doesnt improve c/ exposure
46
Q

second line of defence

A

inflammation, phagocytic white blood cells

  • innate and non-specific
  • communicate c/ third one defence
47
Q

third line of defence

A

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
Q

macrophage

A

immune cell

  • eats foreign particles and displays on cell membrane
  • asks T and B cells if they are foreign or not
49
Q

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

A

first line of defence!

-Mucus, cilia, and macrophage

50
Q

what are nonspecific chemical defences?

A

-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
Q

3 components of innate immunity

A
  1. Antimicrobial proteins
  2. Antimicrobial peptides
  3. White blood cells (leukocytes)
52
Q

immunology

A

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

53
Q

what does healthy immune system do?

A
  • Surveillance of the body
  • Recognition of foreign material
  • Destruction of foreign entities
54
Q

auto-immune disease

A

immune system makes a mistake and attacks body itself

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

55
Q

hoe do cells distinguish between self and foreign particles

A

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
Q

compliment system

A

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

57
Q

antimicrobial peptides (defensins)

  • composition
  • function
  • location
A
  • 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
Q

antimicrobial proteins: cytokines

A

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

  • secrete chemical signals
  • mediate inflammation
59
Q

Interferons

A

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
Q

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

A

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
Q

neutrophils

A

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
Q

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

A

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
Q

T cells

A

cell-mediated immunity

-monocytes that arise from thymus

64
Q

B cells

A

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
Q

Macrophages

A

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
Q

reticuloendothelial system

A
  • Network of connective tissue fibers
  • Provides a passageway within and between tissues and organs
  • White blood cells move through these corridors
67
Q

lymphatic system

A

Immune corridor
Parallels blood system
Dumps into veins near heart

68
Q

what is a meta organism?

A

dynamic microorganism environments sometimes centimetres apart

69
Q

what are the 4 sources of acquiring microbiota?

A

Birth canal
Food
Breathing
environmental contact

70
Q

what three microbes are naturally present in gut?

A

Lactobacilli
Coliforms
Anaerobes

Micro (12 decks)

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