i and d mcqs Flashcards
the lymphoid tissue most closely associated with immune responses to gut pathogens is the:
A- MALT
B lymph nodes
C secondary lymph nodes
D mucosal tissue
E M cells
MALT
the cell type most closely associated with chronic inflammation is the
A basophil
B b cell
C Mast cell
D Nk cell
E macrophage
macrophage
the area of the lymph node closely associated with class switching of antibodies
A medullary sinus
B primary follicle
C secondary follicle
D germinal centre
E paracortex
D germinal centre
the most important target site for penicillin is the
A plasma membrane
B cell wall
C DNA gyrase
D ribosome
E dihydrofolate reductase
B cell wall
one of the following is only found in the uk as an imported fungal infection
A cryptococcosis
B histoplasmosis
Cinvasive candidiasis
D invasive aspergillosis
E pneumocystis infection
b histoplasmosis
the pathogenesis of severe malaria is a consequence of
A reduced circulating levels of inflammatory mediators
B macrophage activation
C over production of tumour necrosis factor il1 il2 and interferon gamma
D toxins produced during infection
E activation of hosts immune system
over production of tumour necrosis factor il1 il2 and interferon gamma
following a routine non complicated surgical procedure scar formation is a result of
A basement membrane disruption as part of surgery
B early mobility
C infection
D healing by secondary infection
E wound dehisence
a basement membrane disruption
the most rapid means of spread of infection in a population is
A sexual transmission
B faecal oral route
C congenital from mother to foetus
D insect bite
E respiratory route via infectious aerosols
E respiratory route via infectious aerosols
negative staining using india ink is used with a light microscope to visualise
A spirochaetes
B capsules
C endospores
D flagella
E pili fimbriae
b capsules
aspergillus species are important in medicine because they
A can invade lung and blood vessels in immunocompromised people
B are ubiquitous environmental fungi
C are thermophiles that can survive being at 55
D produce asexual spores known as conidia
E grow as filaments in a mycelium
A can invade lung and blood vessels in immunocompromised people
the most important characteristic of entamoeba histolytica is that it
A produces cysts which survive in the environment
B can cause mild or asymptomatic diarrhoea
C can cause severe dysentery
D may be acquired via anal sexual activity
E is common in tropical and subtropical countries
c entamoeba histolytica can cause severe dysentery
urinary tract infections have an important impact in the community because they
A can cause recurrent infections in 20-30% women
B rarely caused by anaerobes
C associated with minor anatomical abnormalities of the urinary tract and kidneys of baby boys
D most frequently caused by e coli
E arise because urine is an excellent growth medium
can cause recurrent infections in 20-30% women
capnophiles are bacteria that
A commonly occur in human commensal microflora
B are able to grow in an environment with 2-10% oxygen
C grow in an environment that contains 78% nitrogen
D are aerobic organisms
E require 5-10% of carbon dioxide
E
which one of the following statements is correct
A vertical transmission of viruses between siblings is common in the uk
B most human viruses are readily transmitted to farm animals but the converse is not true
C faeco oral transmission of hepatitis C virus typically occurs in intravenous drug abusers
D transmission can always be prevented by strict personal hygiene
E blood borne viruses may be transmitted noscomially
E
which one of the following statements is correct
A) herpesvirus divides within host cell membranes
B) uncoating is the term used to describe the release of the viral genome from the nucleocapsid
C) negative sense rna acts as viral mrna
D) viral early genes are transcribed after replication of the genome encode structural proteins
E virus replication inevtiably leads to host cell lysis
B
what kind of rna does picornviruses have and what are they
picorn viruses have positive sense single stranded rna which means their rna can directly be used as mrna for protein synthesis by the host’s ribosomes
examples of picornaviruses are
polio
rhinovirus
hepatitis a
coxsackievirus- myocarditis associated
what viruses have reverse transcriptase
hiv
hepatitis b- partially double stranded dna
what kind of symmetry do adenovirus particles exhibit
icosahedral
240 capsomeres
what is pemphigus
rare group of autoimmune diseases which can cause blisters and erosions on the skin and mucous membranes
bodys immune system produces antibodies desmogleins which are proteins that help skin cells stick together
this leads to separation of skin cells acantholysis causing blisters that can rupture and result in painful sores
how many forms of nucleic acid can a single virus agent contain
1
example of aminoglycosides
gentamicin
example of macrolide
erythromycin
example of beta lactam
penicillin
example of tetracycline
doxycycline
example of quinolone
ciprofloxacin
example of glycopeptide
vancomycin
example of anti folate
trimethoprim inhibits bacterial enzyme dihydrofolate reductase
what can aminoglycosides cause
ototoxicity
teratogenicity
prevalence
number of people with disease at one point in time/ number of people in the population at that point in time
rate
number of new people with the disease in a defined period/ person years at risk of disease
what kind of individuals is the live attenuated not recommended to be used on
immunocompromised patients due to the live nature of the vaccine
what are examples of a live attenuated vaccine
bcg
measles, mumps,rubella mmr
influenza (intranasal)
oral rotavirus
oral polio
yellow fever
oral typhoid
what are inactivated preparations vaccines
employ pathogens that have been killed often by heat or chemicals to elicit an immune response
why do inactivated preparation vaccines require boosters
to maintain immunity as the induced immune response is generally weaker than the live attenuated vaccine
what are examples of inactivated preparation vaccines
rabies
influenza (intramuscular)
hepatitis A
what are toxoid (inactivated vaccines)
these vaccines are designed around the toxins produced by certain bacteria. these toxins are detoxified and used as antigens in the vaccine. when the immune system encounters these non toxic toxoids, it learns to combat natural toxins the bacteria produce, providing immunity against the toxic effects of infections
why do toxoid inactivated vaccines require boosters
to maintain immunity since like inactivated vaccines the immune response they induce can wane over time
what are some examples of toxoid inactivated vaccines
tetanus
diptheria
pertussis
what are sub-unit and conjugate vaccines
subunit means that only part of the pathogen is used to generate an immunogenic response. a conjugate vaccine is a particular type that links the poorly immunogenic bacterial polysaccharide outer coats to proteins to make them more immunogenic
what are examples of sub-unit conjugate vaccines
pneumococcus (conjugate)
haemophilus (conjugate)
meningococcus (conjugate)
hepatitis B
human papillomavirus
what is a mrna vaccine
introduce a piece of mrna into cells which then produce a protein to trigger an immune response
what are examples of a mrna vaccine
covid 19 vaccines
what are viral vector vaccines
use a harmless virus (different from target pathogen) to deliver critical parts of the target pathogen to stimulate an immune response
can be produced more rapidly in response to emerging threats
what are examples of viral vector vaccines
-ebola
covid 19
how does the hepatitis B vaccine work
contains hbsag antigen onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant dna technology
what is the life cycle of malaria (brief)
sporozoites
sporozoites mature into schizonts
schizonts contain thousands of merozoites which are released when the liver cell ruptures
inside the rc merzoites develops into trophozoites which matures into schizonts
schizonts undergoes asexual reproduction which produces new merozoites into the bloodstream to infect more rbcs continuing the cycle
what is the dormant form of the malarial parasite found in liver cells
and what two forms of malaria are hypnozoites characteristic of
hypnozoites
plasmodium vivax
plasmodium ovale
what are the two malarial drugs
quinine
chloroquine
when someone is infected with malaria what does the release of hemozoin ( a byproduct of haemoglobin digestion) and other waste products stimulates the immune system causing
cytokine release interlukins and tumour necrosis factor
fever chills and rigors (classic malaria symptoms during paroxysms)
systemic inflammation
what is haptoglobin
protein produced by the liver. binds to free haemoglobin that is released when rbcs are broken down. by binding to haemoglobin haptoglobin helps prevent toxic effects of free haemoglobin in the bloodstream such as kidney damage. it also facilitates removal of haemoglobin-haptoglobin complex by liver and spleen
in phagocytic killing, what is the enzyme that converts hydrogen peroxide and halide ions into bleach
myeloperoxidase
which components form the membrane attack complex
c5b c6 c7 c8 c9
what are three complement pathway outcomes
inflammation
opsonisation
lysis
what components of the complement pathway make up inflammation
c3a c5a
what components of the complement pathway make up opsonisation
c3b c4b
what components of the complement pathway make up membrane attack complex/lysis
c5b, c6 , c7, c9, c8
which cells can produce type 1 interferons
epithelial cells
keratinocytes
fibroblasts
how do scientists differentiate between yeast and mould
moulds are multicellular and filamentous with hyphae whereas yeast are not
at what ph does candida switch from a single cell to a hyphae producing cell
ph8
what is a common cause of vaginal candiadisis
antibiotic usage e.g use of amoxicillin
how does antibiotic usage cause vaginal candiadisis
the typical ph of the vagina is 4 due to lactobacilli producing acids through lactic acid fermentation. antibiotic usage can kill lactobacilli causing the ph to increase and so th candida cells switch to hyphal mode and so infection of mucosal surface
what is a cause of invasive candiadiasis
broad spectrum use antibiotics causing overgrowth of candida
what are virulence factors for streptococcus pyogenes
streptolysin s and o
collagenase
hyaluronidase
what are two examples of cytotoxins (directly poison the cells)
shiga toxin (can cause haemolytic uremic syndrome HUS)
diptheria toxin
what is an example of a neurotoxin
botulinum toxin can cause flaccid paralysis by inhibiting the release of ach neurotransmitter at a neuromuscular junction
Clostridium tetani
what is an example of a enterotoxin
cholera
what is an example of endotoxin
lipopolysaccharide (gram negative bacteria) e coli
how does diptheria toxin cause disease
directly damages the pharynx, myocardium and axons as the toxin inactivates elongation factor -2 which means no proteins are synthesised by ribosomes. this leads to cell death
how can syphilis infection be detected
antibody detection
what is fish
flourescent in situ hybridisation used to detect genetic sequences
what are the stages of wound healing
haemostasis
inflammatory
proliferative
remodelling
what are the stages of viral replication
attachment
penetration
uncoating
expression of viral material
viral assembly
explain the haemostasis phase of wound healing
damaged blood vessel constricts, platelets stick together to seal the leak and coagulation to reinforce platelet plug
explain the inflammatory phase of wound healing
inflammatory blood vessel leaks transudate and removal of damaged cells, pathogens and bacteria,
explain the proliferative phase of wound healing
rebuilding the wound with fibroblasts and ecm fibroblast migration and angiogenesis which results in granulation tissue, release of growth factors, and the epithelisation of wounds and then differentiation of fibroblasts to myofibroblasts myofibroblasts allow the wound to draw in and contract
explain the remodelling phase of wound healing
remodelling involves collagen fibres realigning along tension lines, the replacement of type 3 collagen by type 1 cross linking of collagen fibres and closure of the wound
what intention injury is a surgical wound
primary intention
what intention injury is a burn
secondary intention
what intention injury is a surgical wound complicated by infection
primary delayed closure
what intention wound is pancreatitis surgical wound
primary delayed closure
are osteoclasts multinucleated
yes
what is the most common cause of delayed wound healing
infection
which class of antibiotics inhibit transpeptidases and transglycosylases involved in cross-linking NAG and NAM subunits with short chains of amino acids thus reducing strength of cell wall and leading to osmotic rupture
beta lactams
what is the mechanism of action of tetracyclines
binds to 30s ribosome inhibits aminoacyl trna from binding to mrna ribosome by binding to 30s subunit
what is an adverse affect of tetracyclines
teeth discolouration as they bind to calcium ions in developing teeth and bones
mrsa has mutated so what antibiotic is it no longer effected by
beta lactams
what is a morphological pattern of chronic inflammation
granulomatus inflammation
what kind of infection out of latent chronic and acute can hepatitis b and hiv lead to
chronic infection
what kind of infection can sars cov 2 lead to
acute infection
what kind of infection can epstein barr and hepes simplex to out of acute latent and chronic
latent infection
what is the order in size of bacteria protozoa viruses helminths
viruses
bacteria
fungi
protozoa
helminths
what is giardia
protozoa commonly found in bodies of water inhabited by beavers. beavers are carriers and cysts contaminate water
what type of exotoxin is clostridium tetani and how does it cause disease
clostridium tetani is a neurotoxin and inhibits release of gaba and glycine at neuromuscular junction causing spastic paralysis lockjaw respiratory paralysis
tetanospasmin toxin
what type of exotoxin is cholera and how does it cause disease
enterotoxin
damages sodium glucose co transporter in the gut epithelium
what type of exotoxin is shiga toxin and how does it cause disease
destroys ribosomes
cytotoxin
when it gets to gut epithelium it can lead to bloody diarrheoa when it destroys endothelium it can cause haemolytic uremic syndrome
what type of exotoxin is diptheria and how does it cause disease
cytotoxin
directly damages the pharynx the myocardium and axons as the toxins inactivate elongation factor -2 which means no proteins are synthesised by ribosomes this leads to cell death
what is rna dependent rna polymerase
converts negative sense rna to positive sense rna so that it can be translated
what viruses contain reverse transcriptase
hiv hepatitis b
how are cryptococcus, streptococcus pneumoniae neiserria mengitidis detected
antigen testing
what do follicular t helper cells do
help b cells make specific antibodies
what do th17 cells do
they activate nuetrophils
what do th1 cells activate
macrophages, cytotoxic t cells
what do th2 cells activate
mast cells, eosinophils, ige
