uWorld 29 Flashcards
organ susceptibility to infarction after occlusion of a feeding artery is ranked from greatest to least how?
CNS, myocardium, kidney, spleen and LIVER (least likely)
why are infarcts in otherwise normal liver rare
DUAL BLOOD SUPPLY
what are microvilli made up of
actin
what is Nissle substance
RER in neurons
what is an examples of enhanced ability to penetrate bacteria due to synergism
penicillins stopping peptidoglycan cell wall synthesis allowing aminoglycosides to gain access to the cell interior, where they act on the 30S subunit of the bacterial ribosome
what are the two pathways of angioedema
mast cell activation (Type 1 hypersensitivity, direct mast cell activation- like opioids)
-associated pruritic and urticaria
excess bradykinin (ACEI, C1 inhibitor deficiency) -NO pruritic and urticaria
what type of hypersensitivity is acute hypersensitivity pneumonitis (and what causes it)
specific serum IgG antibodies that precipitate bacterial or fungal antigens found in inhaled organic dust particles
causes interstitial alveolitis and bronchiolitis via IMMUNE COMPLEX and COMPLEMENT DEPOSITION in vessel walls (Type III Hypersensitivity)
what causes a bruise to change color from bluish to greenish
HEME OXYGENASE (contained in macrophages and some other cells) degrades heme to BILIVERIDEN, CO, and Fe3+
biliveriden is GREEN in color and is further reduced (by biliverdin reductase) to bilirubin (yellow pigment) which is transferred to liver bound to albumin
what is seen in acute and chronic vitamin A toxicity (overdose)
Acute: nausea, vomiting, vertigo, blurred vision
Chronic: alopecia, dry skin, hyperlipidemia, hepatotoxicity, hepatosplenomegaly, visual difficulties
PAPILLEDEMA when present is suggestive of CEREBRAL EDEMA in the setting of bending intracranial hypertension (PSEUDOTUMOR CEREBRI)
large doses of vitamin C are associated with what
false negative stool guaiac results
diarrhea
abdominal bloating
maybe calcium oxalate nephrolithiasis
large doses of vitamin E are associated with what
higher mortality rates due to hemorrhagic stroke in adults
higher rates of necrotizing enterocolitis in infants
What is BLOOM syndrome
AR disorder of mutation in BLM gene that encodes for DNA HELICASE (enzyme responsible for unwinding of the double helix)
chromosomal instability and breakage manifesting as: GROWTH RETARDATION FACIAL ANOMALIES (microcephaly) PHOTOSENSITIVE RASH IMMUNODEFICIENCY (recurrent infections)
what prevents reannealing of the ssDNA during replication
ssDNA-binding proteins- they bind to and stabilize the ssDNA, preventing it fro reannealing
what does topoisomerase do
relieves tension in supercoils by introducing transient single- or double-stranded nicks in the DNA (located ahead of helices on the dsDNA segment of the relocation fork)
what is the treatment of choice for specific phobia
behavioral therapy (systematic, repeated exposure to the phobic stimulus)
typically done in a step-wise manner, resulting in decreased anxiety over time as habituation and extinction occur
can be done in vivo (most effective), imaginal, or virtual reality
cutaneous neurofibromas are predominately comprised of what
they are benign nerve sheath neoplasms made up mostly of SCHWANN CELLS (NEURAL CREST derivatives)
the neural tube gives rise to what
neurons of CNS neurohypophysis retina pineal gland preganglionic autonomic fivers astrocytes ependymal cells
the vertebrae are derived from what
paraxial mesoderm
the surface ectoderm gives rise to what
epidermis lens of eye outer layer of cornea nasal and oral epithelium olfactory epithelium inner ear sensory organs anal epithelium below the dentate line Rathkes pouch salivary, sweat, and mammary glands
what are acute dystonia and akathisia
acute dystonia:
- 3-4 days after starting
- distressing, sustained, involuntary contraction of the neck, mouth, tongue, or eye muscles
akathisia- physical restlessness, difficulty sitting still, compelling need to move
how does the kidney try and make up for metabolic acidosis
increased HCO3- resorption
increased H+ secretion
increased acid buffer excretion ((HPO4)2- and NH3 which get excreted as H2PO4- and NH4+)
what are PROTHROMBIN COMPLEX CONCENTRATES
contain the vitamin K-dependent factors II, VII, IX, and X
can be used in bleeding due to WARFARIN OVERDOSE (along with fresh frozen plasma)
what do aminocaproic acid and tranexamic acid do
inhibit fibrinolysis by inhibiting plasminogen activation (tPA, alteplase, reteplace, streptokinase, tenecteplase)
what anticonvulsants should be avoided in someone with juvenile myoclonic seizures (and all generalized epilepsy syndromes for that matter) and why
narrow-spectrum anticonvulsants (phenytoin, carbamazepine, gabapentin, phenobarbital)
they can aggravate seizures
what is used to treat juvenile myoclonic epilepsy (JME)
broad-spectrum anticonvulsant
VALPROIC ACID, lamotrigine, levetiracetam, topiramate
what is fluphenazine
dopamine antagonist (typical antipsychotic)
used to treat Tourette syndrome
in a patient with known mitral stenosis what finding in the heart is suggestive of aortic valve involvement too
left ventricular DIASTOLIC PRESSURE INCREASE
b/c this would be normal or decreased in mitral stenosis alone