EMS lectures 7,8,9, 10

Question 1

What is healing by regeneration

Answer 1

tissue returns to normal as damage is replaced by same cells

restituation of specialised function

Question 2

what is healing by repair

Answer 2

tissue replaced by fibrosis and scaring

loss of specialised function

Question 3

Describe a labile cell population

Answer 3

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

Question 4

Describe a stable cell population

Answer 4

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

Question 5

Describe a permanent cell population

Answer 5

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

Question 6

what is crucial to regeneration?

Answer 6

survival of stem cells

tissue kinetics and architecture

Question 7

explain the formation of granulation tissue

Answer 7

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

Question 8

what are factors inhibiting healing

Answer 8

Local

• blood supply
• haematomoa
• forgein body
• mechanical stress
• infection

Systemic

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

Question 9

what is healing by 1st intention

Answer 9

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

Question 10

what is healing by second intention

Answer 10

wound not apposable
increased granulation reaction
extensive scarring

Question 11

how does wound strength progress

Answer 11

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

Question 12

How does fracture healing occur

Answer 12

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

Question 13

How does healing occur in the brain

Answer 13

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

Question 14

what is the commensal microbiota

Answer 14

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

Question 15

What are Koch’s postulates

Answer 15

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

Question 16

Koch’s postulates with regards to genes

Answer 16

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

Question 17

Explain a Virus

Answer 17

obligate intracellular parasite

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

Question 18

Explain Microfungi

Answer 18

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

Question 19

what are the protista

Answer 19

unicellular eukaryotes

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

Question 20

What is caused by Trichomonas vaginalis

Answer 20

foul smelling vaginal discharge and vaginal infection

Question 21

What type of microorganism is Pneumocystis jiroveci (carinii)

Answer 21

FUNGUS

Question 22

what does streptococcus mutants produce to help stick to teeth?

Answer 22

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

Question 23

what do “coagulase negative staphylococci” produce and where do they live?

Answer 23

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

Question 24

Explain bacteria

Answer 24

prokaryotes

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

if encapsulated = protective from phagocytes

Question 25

Routes by which infection can be spread

Answer 25

faecal oral
Sexually
direct innoculation
airborne
animal to human

Question 26

What is a Zoonoses?

Answer 26

A bacterial reservoir in an animal that is disease causing

Question 27

What is a Fomite

Answer 27

inanimate object used as a vector for the spread of disease

Question 28

What is an intoxication illness

Answer 28

disease caused by exposure to a toxin not a microorganism

- tetanus, botulism

Question 29

What type of toxins are produced by bacteria

Answer 29

endotoxin

exotoxin

Question 30

Define normal flora

Answer 30

organisms found in a given location in a state of health

Question 31

define colonisation

Answer 31

establishment at a site in the bodt

Question 32

define symobiosis

Answer 32

two or more organisms coexist in close physical association

Question 33

what are the types of symbiosis

Answer 33

Mutualism
Neutralism
Commensalism
Parasitism

Question 34

Difference between non sterile and sterile sites?

Answer 34

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

Question 35

what is tissue tropism

Answer 35

the propensity that a specific organism grows in an area

Question 36

what are the physical variables that affect microenvironment?

Answer 36

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

Question 37

What are the normal skin flora

Answer 37

Coagulase-negative staphylococci (staph. epidermis)

• staph aureas (nasal)
• propionibacterium acnes

Question 38

normal mouth flora

Answer 38

viridans
oral streptococci
anaerobes
+ many others

Question 39

common flora of nasopharyngeal

Answer 39

Nostrils - skin flora, Staph aureus

Pharynx - respiratory and pathogens

• strep pyogenes group A
• haemophilus influenzae
• step pnuemoniae
• neisseria meningitidis
• s. aureus

Question 40

Normal Vaginal flora

Answer 40

Prepuberty - skin flora, lower GI flora

Post puberty

• oestrogens produce glycogen changes environment
• Lactobacillus Spp = maintains pH 3
• skin flora
• candida albicans

Question 41

GI - stomach and small intestine flora

Answer 41

low pH prevens bacterial growth

• acid tolerant lactobacilli
• helicobacter pylori

Question 42

GI large intestine flora

Answer 42

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

Question 43

benefits of normal flora

Answer 43

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

Question 44

C diff - infection

Answer 44

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

Question 45

What can be used to treat C diff

Answer 45

Vancomyocin

Faecal transplant

Question 46

Pathology of normal flora

- Types

Answer 46

Overgrowth - Thrush
Translocation - conjunctivitis
Cross Infection - MRSA

Question 47

conditions caused by normal flora

Answer 47

dental cavities, pharyngitis, endocarditis, abscesses, pneumonia