EMS lectures 7,8,9, 10 Flashcards Preview

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Flashcards in EMS lectures 7,8,9, 10 Deck (47):
1

What is healing by regeneration

tissue returns to normal as damage is replaced by same cells

restituation of specialised function

2

what is healing by repair

tissue replaced by fibrosis and scaring

loss of specialised function

3

Describe a labile cell population

High cell turnover
active stem cell population
excellent regenerative capacity
e.g. epithelia

4

Describe a stable cell population

low cell turnover - can be inc
good regenerative capacity
liver/renal tubules

5

Describe a permanent cell population

No cell turnover
long life cells
NO regenerative capacity
e.g. neurones, muscle cells

6

what is crucial to regeneration?

survival of stem cells
tissue kinetics and architecture

7

explain the formation of granulation tissue

endothelial proliferation > new vessels > macrophage debridement > proliferation of myofibroblasts > collagen and EMC synthesised> myofibrils gain contractile ability --> wound contraction

8

what are factors inhibiting healing

Local
- blood supply
- haematomoa
- forgein body
- mechanical stress
- infection

Systemic
- diabetes
- anaemia
- malnutrition
- trace metal deficiet
- Vit C deficit
- catabolic state
- drugs
- age

9

what is healing by 1st intention

clean uninfected surgical wound,
wound edges apposed
good haemostats
= neat scar in a couple of weeks

10

what is healing by second intention

wound not apposable
increased granulation reaction
extensive scarring

11

how does wound strength progress

day 7 =10% sutures out
week 4 = 70%
week 12 = 80%

12

How does fracture healing occur

1) organised haematoma
2) removal of necrotic fragments
3) osteoblasts deposit woven bone - callus
4) callus remodelled by mechanical stress
5) callus replaced by lamella bone

13

How does healing occur in the brain

Neurons = terminally differentiated
cyst formation
Gliosis = proliferation of astrocytes (not scarring)

14

what is the commensal microbiota

the 90% of cells in the human body that are not of human origin
- flora associated varies depending on anatomical site

15

What are Koch's postulates

1) causative organism can be isolated from every individual with disease
2) organism can be cultured artificually in lab
3) cultured organism causes disease when inoculated into person
4) cultured organism can be extracted from person inoculated

16

Koch's postulates with regards to genes

Gene encode virulence factors
1) gene encoding train of interest must be presents and translated in a virulent strain
2) if gene not present or silent - strain should not cause disease
3) disruption of gene in virulent strain - incapable of causing disease
4) introduction into previously non pathogen stain causes transformation to virulence
5) gene is expressed during infection
6) antibodies raised against gene are protective against disease

17

Explain a Virus

obligate intracellular parasite
- nucleic acid core (RNA or DNA)
- protein coat - made of capsomeres
- retroviruses - rare
- plant viruses = viroids

18

Explain Microfungi

- eukaryotic
- cell walls made of chitin
- hairy growths = mould
- filaments of mould = hypae
- group of hypae = mycelia
- moulds = ringworm, atheletes foot
unicellular fungi - yeast

19

what are the protista

unicellular eukaryotes

1) apicoplxa (sporoza)
2) flagella protista
3) ciliate prostae
4) Amoebae

20

What is caused by Trichomonas vaginalis

foul smelling vaginal discharge and vaginal infection

21

What type of microorganism is Pneumocystis jiroveci (carinii)

FUNGUS

22

what does streptococcus mutants produce to help stick to teeth?

thick slime - helps to form plaque and eventually leads to dental cavities

23

what do "coagulase negative staphylococci" produce and where do they live?

on the skin
produce slime that enable them to stick to plastic
- associated with infection from implanted plastic medical devices

24

Explain bacteria

prokaryotes
- cocci = round,
- bacilli = rod
- gram -ve = pink = 2 membranes
- gram +ve = purple = 1 membrane

if encapsulated = protective from phagocytes

25

Routes by which infection can be spread

faecal oral
Sexually
direct innoculation
airborne
animal to human

26

What is a Zoonoses?

A bacterial reservoir in an animal that is disease causing

27

What is a Fomite

inanimate object used as a vector for the spread of disease

28

What is an intoxication illness

disease caused by exposure to a toxin not a microorganism
- tetanus, botulism

29

What type of toxins are produced by bacteria

endotoxin
exotoxin

30

Define normal flora

organisms found in a given location in a state of health

31

define colonisation

establishment at a site in the bodt

32

define symobiosis

two or more organisms coexist in close physical association

33

what are the types of symbiosis

Mutualism
Neutralism
Commensalism
Parasitism

34

Difference between non sterile and sterile sites?

non sterile = have normal flora
- exposed to environment
- no mechanism to maintain sterility
- conjunctiva, GI tract, vagina, skin, nasopharynx

sterile - no normal flora
- maintained by surface cleaning
lower respiratory tract
- maintained by unidirectional flow created by barriers
cervix, urethra, eustachian tube
- maintained by physical separation from non sterile sites
plural cavity, spinal cord meninges

35

what is tissue tropism

the propensity that a specific organism grows in an area

36

what are the physical variables that affect microenvironment?

moisture, temperature, pH, o2 availability, nature of surface

37

What are the normal skin flora

Coagulase-negative staphylococci (staph. epidermis)
- staph aureas (nasal)
-propionibacterium acnes

38

normal mouth flora

viridans
oral streptococci
anaerobes
+ many others

39

common flora of nasopharyngeal

Nostrils - skin flora, Staph aureus

Pharynx - respiratory and pathogens
- strep pyogenes group A
- haemophilus influenzae
- step pnuemoniae
- neisseria meningitidis
- s. aureus

40

Normal Vaginal flora

Prepuberty - skin flora, lower GI flora

Post puberty
- oestrogens produce glycogen changes environment
- Lactobacillus Spp = maintains pH 3
- skin flora
- candida albicans

41

GI - stomach and small intestine flora

low pH prevens bacterial growth
- acid tolerant lactobacilli
- helicobacter pylori

42

GI large intestine flora

10(9)-10(11) organisms/gram
95% anaerobes
areobic bacteria - Enteric gram -ve bacilli (E.coli, enterobacter spp, proteus spp)

43

benefits of normal flora

synthesis and excretion of vitamins (K and B12 from enteric bacteria)
- colonisation resistance (environmental manipulation e.g. pH)
- Induction of cross reactive antibodies - protective effect

44

C diff - infection

-hospital acquired
-usually affects >60yo
-antibiotic treatment = RISK
(inhibition of colonization resistance)
-toxin produces - diarrhoea
pseudomembranous colitis

45

What can be used to treat C diff

Vancomyocin
Faecal transplant

46

Pathology of normal flora
- Types

Overgrowth - Thrush
Translocation - conjunctivitis
Cross Infection - MRSA

47

conditions caused by normal flora

dental cavities, pharyngitis, endocarditis, abscesses, pneumonia