Test 16 Flashcards
(48 cards)
Why do hepatitis C antibodies NOT confer effective immunity against the infection?
There’s a large variety in hep C virus envelop proteins, so the host Abs always lag behind the production of new mutant strains of HCV making it REALLY hard to confer immunity.
A 34 y/o immigrant presents w/ patchy areas of skin anesthesia and hypopigmentation on his upper extremities. Nerve biopsy shows bacteria invading SCHWANN cells.
Myobacterium leprae
grows best at temps slightly lower than body temp so it commonly effects extremities
What limits tuberculoid leprosy?
Least severe form
Limited by intact cell mediated immune system
In what type of pts does lepromatous leprosy occur in?
pts w/ a weak cell mediated Th1 immune response–mphages are nevere given the signal to kill myobacterial organisms so it disseminates (lionized facies)
What spirochete is responsible for Lyme disease?
Borrelia burgdorferi
What spirochete is responsible for syphilis?
Treponema pallidum
Describe the progression of syphilis.
Painless chancre> diffuse eruption of erythematous macules (palms and soles) and formation of conyloma lata> gummas of skin and bone, aortitis, neurosyphilis
What gram - rod causes mild enteritis in immunocompetent pts and mild systemic bacteremic illness in immunocompromised pts?
Campylobacter fetus
A 64 yearl old man loses consciousness b/c of low bp while buttoning his tight collar shirt. What afferent nerves are responsible for this?
External pressure on the carotid sinus of the internal carotid area stimulates baroreceptors in the carotid sinus walls>
CN 9>
vasodilation, decrease in heart rate/contractility/decrease in bp
Where do fibers from both the carotid sinuses and aortic arch baroreceptors terminate?
Both CN 9 and CN 10 terminate on the solitary nucleus of the medulla
What lies immediately deep to the tip of the 12th rib on the left?
kidney
11/12th ribs are floating ribs–the distal tip fo the 12th rib can be displaced into the retroperitoneum when fractured and LACERATE the kidney
lies under the 9th, 10th, 11th ribs
spleen
lies under the 8, 9, 10, 11 rib
liver
fractures of 1st through 6th ribs may damage…
visceral pleura
What type of trauma causes pancreatic damage?
crushing abdominal damage
What method is used in designing case-control studies to control for confounding?
Matching: Selecting variables that could be confounders (age, race), so that there is a similar distribution
Cases (pt’s w/ CRC) are matched w/ controls (neighbors) of similar age and race–also accounts for socioeconomic status/environmental factors
What is a confounding variable?
A factor related to BOTH the exposure and the outcome but NOT the casual pathway
Lactic acidosis
Raged red skeletal muscle fibers
Mitochondrial myopathy
Heteroplasmy
Coexistence of both mutated and WT versions of mitochondrial genomes in an individual cell> variable expression in a mitochondrial related disease
All invdividuals with a given gene express its phenotype
full penetrance
Presence of genetically distinct cell lines in the same individual
mosaicism
A pt has a mutation that affects G protein signaling and presents w/ unilateral cafe-au lait spots, polyostotic fibrous dysplasia, precocious puberty and multiple endocrine abnormalities.
McCune Albright Syndrome
Both members of a given pair of nuclear chromosomes are inherited from the same parent
Uniparental disomy
Bounding femoral pulses and carotid pulses accompanied by head bobbing
Water hammer pulses w/ each heart beat are signs of aortic regurgitation d/t LARGE LV stroke volume
