MoD lectures 8-12 Flashcards

1
Q

What are the two ways cells heal after inflammation?

A

regeneration and repair

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2
Q

What is regeneration?

A

damaged cells replaced by like so tissue returns to normal –> restitution of specialist function

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3
Q

What is repair?

A

damaged cells cannot be replaced by like so fibrosis and scarring –> loss of specialized function

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4
Q

What are the properties of labile cell populations and name some examples

A
  • high normal cell turnover so maintain their integrity
  • active cell populations sitting in the basal zone
  • e.g. epithelia
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5
Q

What are the properties of stabile cell populations and name some examples

A
  • low physiological turnover but can switch on turn over when the need arises
  • e.g. liver and renal tubules
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6
Q

What are the properties of permanant cell populations and name some examples

A
  • no physiological turnover, very long life cells

- e.g. neuron and muscle cells

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7
Q

Which type of cells are best at regeneration and which are worst?

A

best: labile
stabile
worst: permanant

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8
Q

What are adult stem cell niches?

A

reservoirs of adult stem cells present in adult tissues in specific anatomical places–> the survival of this is crucial to regeneration

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9
Q

What does uncontrolled cell division lead to?

A

neoplasia

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10
Q

Name some examples for how regeneration is controlled

A

contact inhibition (cells proliferate until they touch each other) and using growth factors, cell-cell and cell-matrix interactions

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11
Q

What is granulation tissue?

A

new connective tissue that forms on the surfaces of wounds during healing
it matures into a fibrous scar

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12
Q

What 3 components make up granulation tissue?

A
  • new capillary loops
  • phagocytic cells to remove dead tissue (neutrophils and macrophages)
  • (myo)fibroblasts to lay down matrix components (e.g. collagen)
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13
Q

What is a catabolic state?

A
state of breaking down larger molecules to smaller ones
proteins- amino acids
fats- fatty acids
glycogen- gluose
e.g. corticol steroids.
This interacts with the healing process
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14
Q

What is primary intention healing?

A

-healing of a clean, uninfected surgical wound with good haemostasis with edges apposed

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15
Q

What is organisation?

A

The formation of a fibrous scar and converting to a fibrous scar

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16
Q

What is secondary intention healing?

A

the wound edges are not opposed causing more extensive scarring

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17
Q

What cells form a callus?

A

osteoblasts which lay down woven bone (callus) which is then replaced by lamellar bone

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18
Q

What is the supporting tissue in the brain?

A

glial cells instead of collagen and fibroblasts etc

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19
Q

What does damaged tissue form in the brain?

A

a cyst

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20
Q

What is gliosis?

A

proliferating of astrocytes in the brain (instead of scarring)

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21
Q

Name some local factors which inhibit healing

A

infection, haematoma, blood supply, foreign bodies, mechanical stress

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22
Q

Name some systemic factors which inhibit healing

A

age, drugs, anaemia, diabetes, malnutrition, catabolic states, vit c deficiency, trace metal deficiency

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23
Q

What is an akaryote?

A

cell without a nucleus e.g. RBC

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24
Q

What is a prokaryote?

A

microscopic single-celled organism which has neither a distinct nucleus with a membrane nor other specialized organelles

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25
Q

What is a eukaryote?

A

organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus

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26
Q

What are virulent micro-organisms?

A

microorganisms which cause disease

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27
Q

What is Koch’s postulates?

A

criteria used to describe if a microorganism caused disease
1 the causative organism must be isolated from every individual suffering from the disease in question
2. the causative organism must be cultivated artificially in pure culture
3. When the causative organism, is inoculated from pure culture, the typical symptoms of the infection must result
4. the causative organism must be recoverable from individuals who are infected experimentally

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28
Q

What organism causes syphilis?

A

treponema pallidum

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29
Q

What causes typhoid fever?

A

salmonella typhi

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30
Q

What is the protein coat that surround the nucleic acid core of a virus made up of?

A

capsomeres

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31
Q

What is a virus envelope made up of?

A

lipid and usually derived from the cell in which they grow

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32
Q

What is the nucleic acid core of a virus made up of?

A

DNA or RNA but not both

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33
Q

How are retroviruses different from normal ones?

A

the virion carries an RNA copy of the genome but upon infection of a host cell a cDNA copy of the virus genome is made using reverse trancriptase

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34
Q

what are bacteriophages?

A

special class of bacteria which attacks viruses

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35
Q

What are viroids?

A

naked, infectious RNA molecules that are not associated with any proteins, commonly attack plants

36
Q

What are prions?

A

a small infectious particle that is a disease-causing form of a protein called cellular prion protein (PrPc)

37
Q

What is another name for prion diseases?

A

transmissible spongiform encephalopathies (TSE’s)

including: CJD, scarpie and BSE

38
Q

What is a microfungi cell wall made up of?

A

chitin: a polymer of N-acetyl glucosamine that is found in the cell wall of the majority of fungi

39
Q

What are two superficial infections that mould causes?

A

ringworm and athletes foot

40
Q

What is thrush caused by?

A

candida albicans

41
Q

What are moulds?

A

fungi that grow inmats of tiny filaments known as hyphae or myselia. They may be subdivided into separate compartments by corss walls known as septa

42
Q

What are protists?

A

unicellular eukaryotes

43
Q

What are the 4 classes of protista?

A

apicomplexa
flagellate protista
ciliate protista
amoebae

44
Q

What are the 3 basic shapes that a bacteria can adopt?

A

round- cocci
rod-shaped bacilli
spiral

45
Q

How does the gram stain affect gram pos and gram neg bacteria?

A

gram pos retain the purple iodine dye complex when treated with acetone or alcohol and gram neg don’t so turn pink

46
Q

What does the envelope of gram positive comprise of?

A

peptidoglycan
interlinked sugar molecules and short peptides containing both D- and L- amino acids
teichoic and teichuronic acides

47
Q

What is responsible for gram negative shock?

A

lipid A which acts as an endotoxin

48
Q

What is dental caries caused by?

A

streptococcus mutans

it produces extracellular slime to allow it to stick to teeth

49
Q

What GI infections are spread through the faecal oral route?

A

typhoid, scholera, dysentry, hep A and poliomyelitis

50
Q

What is a zoonosis?

A

disease which can be spread from animals to human

51
Q

What are fomites?

A

objects or materials which are likely to carry infection

52
Q

How do bacteria stick to surfaces?

A

pili and fimbrae

53
Q

define symbiosis

A

two or more organisms co-exist in a close physical association

54
Q

define mutalism

A

both organisms benefit from symbiosis

55
Q

define commensalism

A

one organisms benefits, the other derives no harm or benefit

56
Q

define neutralism

A

neither organism derives harm or benefit

57
Q

define parasitism

A

one organism benefits are the expense of the other

58
Q

define tissue tropism

A

propensity for a particular organism to grow in a particular habitat

59
Q

What is the difference in normal flora between breast fed babies and bottle-fed babies

A

breast-fed: predominanttly bifidobacteria and lactobacillus

bottle-fed: more enterobacteriacae

60
Q

Name some skin flora

A

coagulose negative staphylococci (staphylococcus epidermis)
staphylococcus aureus
propionibacterium acnes

61
Q

Name some pharynx flora

A
streptococcus pyogene (gorup A)
haemophilus influenzae
streptococcus pneumoniae
neisseria meningitidis
s. aureus
62
Q

What bacteria are in the stomach or small intestine?

A

acid tolerant lactobacilli
helicobacter pylori
predominantly aoerobic, low gastric pH inhibits bacterial growth

63
Q

What is the most common type of bacteria in the large intestine?

A

anaerobes: bacteriodes spp, clostridium spp, bifidobacteria spp

64
Q

What secretes vit b12 and k?

A

enteric bacteria

65
Q

What is the best treatment for C.difficile?

A

faecal transplants (+/- vancomyacin)

66
Q

What are 3 ways that normal flora can cause disease?

A
  1. overgrowth e.g. vaginal thrush
  2. translocation e.g. conjunctivitis
  3. cross infrection e.g. MRSA
67
Q

What clinical conditions are caused by normal flora?

A

abscesses, pneumonia, gastroenteritis, peritonitis, urogenital infections, endocarditis, dental caries, peridontal disease, pharyngitis

68
Q

What is pathogenicity?

A

the capacity of a micro-organism to cause an infection.

It requires: transmissibility, establishment in or on a host, harmful effect, oresistence

69
Q

What is a pathogenic organism?

A

organisms of sufficient virulence

70
Q

What is infectivity?

A

the ability of a micro-organism to become established in/on a host

71
Q

What are virulence factors?

A

components of micro-organisms that result in the harmful effects

72
Q

What is the dose of an organism that would cause death?

A

LD50

73
Q

What is the dose of an organism that would cause infection?

A

ID50

74
Q

define colonisation

A

the process of an organism becoming maintained on or in a host

75
Q

Name 3 receptor-ligand interactions between a micro-organism and a host cell that causing colonisation

A

E.coli P fimbrae: glyoclipids on human uroepithelial cells
S pyogenes protein- F : fibronectin 1 in connective tissue
influenza haemagglutin : respiratory epithelial sialic acid receptors

76
Q

What is the active component in endotoxins?

A

lipopolysaccharide- LPS. Consists of lipid A, oligosaccharide cor and polysaccharide “o” antigen
lipid A causes harm

77
Q

What is systemic inflammatory response syndrome? (SIRS)

A

the host response to endotoxin, emcompases imprecise terms like septic shock and endotoxic shock
causes: uncontrolled cytokine release, hypotension, fever, cardiac and/or renal failure, uncontrolled activation of clotting cascade, DIC

78
Q

what are exotoxins produced by?

A

living bacteria

79
Q

What is botulism caused by?

A

clostridium botulinum (gram pos baccilus, anaerobe)

80
Q

What are the clinical presentations of botulism? (5 D’s)

A
diplopia
dysphagia
dystharia
dry mouth
death (due to respiratory failure)
81
Q

What is tetanus caused by?

A

clostridium tetani

82
Q

How does the clinical presentation differ between tetanus and botulism?

A

botulism causes flaccid paralysis and tetanus causes rigid paralysis ‘opisthotonis’

83
Q

Name the causes of these exotoxin-mediated infections

a) cholera
b) diphtheria
c) whooping cough
d) scarlet fever

A

a) vibrio cholerae
b) corynebacterium diptheriae
c) bordetella pertussis
d) streptococcus pyogenes

84
Q

Name s.pyogenes virulence factors (5)

A
  • hyaluronidas and streptokinase (breaks down connective tissue)
  • C5a peptidase (inactivates C5a)
  • erythrogenic toxin (causes rash of scarlet fever)
  • toxic shock syndrome toxin
85
Q

Which micro-organisms evade the immune system by inhibit phagocytosis?

A

s. pyogenes and s. pneumoniae

86
Q

Which micro-organisms evade the immune system by hiding in host cells?

A

mycobacterium tuberculosis, salmonella typhi and listeria monocytogenes