test 12 or 13 Flashcards
fanconi anemia
DNA repair defect that causes an aplastic anemia. these patients are extremely sensitive to alkylating agents and have significant chromosomal breakage, rearrangements, and deletions. patients also have small heads, small, wide thumbs, small eyes, high fetal Hb concentration, small kidneys, pigmented patches on their abdomens, hypogonadism.
What are important complications of subarachnoid hemorrhage?
secondary arterial vasospasm. this vasospasm occurs in the vessels surrounding the ruptured aneurysm. it may cause cerebral ischemia, which presents as new-onset confusion and/or focal neuro deficits 4-12 days after the initial insult. it may not appear on CT- requires doppler testing. tx: nimodipine
also consider rebleeds. Rebleeds will be visible on CT.
autosomal dominant vs. autosomal recessive polycystic kidney disease
dominent: PKD1 or PKD2 mutations. cysts appear at any point along the nephron but less than 5% of nephrons are affected. cysts are microscopic at birth but eventually enarge to compress the renal parenchyma and cause atrophy and fiborsis. may also involve LIVER CYSTS and CEREBRAL ANEURYSMS.
Autosomal recessive kidney disease presents at birth or during the first year of life with bilateral flank masses. cysts are formed by dilated distal tubules and collecting ducs.
aortic and carotid arch receptors
aortic arch transmits via vagus nerve to the solitary nucleus of the medulla. it responds only to increases in blood pressure.
carotid sinus is a dilated region at the carotid bifurcation. it transmits via the glossopharyngeal nerve to the solitary nucleus. it responds to increaes and decreases in blood pressure
What chemoreceptors are involved in regulation of breathing?
caroid and aortic bodies are stimulated by decreased PO2, increased PCO2, and decreased pH in the blood. they take over in patients with chronic hypercapnia.
central chemoreceptors: stimulated by changes in pH and PCO2 of brain interstitial fluide, which is influenced by CO2. Do NOT respond directly to oxygen.
What is a diagnostic deficiency of paroxysmal nocturnal hematuria?
deficiency of CD55 and CD59 becasue of lack of anchoring protein GPI. these patients have inappropriate activation of complement agains the RBCs and show anemia, thrombocytopenia, hypercoagulability, and pancytopenia (this is a stem cell disorder).
What are some causes of non-caseating granulomas?
Crohn’s disease, foreign body, sarcoidosis, beryllium, cat scratch disease
describe the innervation of the ear (sensation only)
external auditory canal and external tympanic membrane: manidibular portion of trigeminal nerve.
posterior external auditory canal: CNX
inner surface of tympanic membrane: CNIX
stapes vs. tensor tympani
stapes: innervated by CNVII. helps prevent hyperacusis
tensor tympani: innervated by CNV. helps prevent you from hearing your own chewing too loudly; draws tympanic membrane medially.
complications of endometriosis
pain with menstruation; adhesions and distortion of organ structure. nodularity of the uterosacral ligaments and fixed retroversion of the uterus are commonly found (important!). dyspareunia is related to retroversion of the uterus and endometrial implants. dyschezia (painful defecation) may occur d/t pelvic adhesions. patients may have difficulty conceiving because of adhesions. ectopic tissue secretes prostaglandins that can also interfere with ovulation and tubual function.
adenomyosis: uterus will be enlarged (endometrial glands in uterin myometrium)
What happens after thyamine dimers have been formed?
ultraviolet-specific endonucleases detect abnormalities in DNA structure caused by formation of DNA photoprotducts and then excise the defective region. the enzyme nicks damaged sites, which are later excised by the 5’ to 3’ exonuclease activity of DNA pol.
signs of reversible cell injury to the myocardium
myofibril relaxation (because of intracellular ATP depletion and lactate accumulation)
disaggregation of polysomes (dissotionof of rRNA from mRNA)
disaggregation of nuclear granules
clumping of nuclear chromatin
glycogen loss
function of retionblastoma protein
normally binds the E2F protein, which must be free for the transition from G to S phase to occur.
Rb is inactivated by phosphorylation. Rb phosphorylation occurs in response to cyclin D, E and CCK activation. therefore, a cell in the S phase must have recently phosphorylated the Rb gene.
types of congenital QT syndromes
Lange-Nielsen: autosomal recessive with sensorineural deafness
or Romano-Ward: autosomal dominant without deafness.
cyanide poisoning
- nitrites oxidize Hb to methemoglobin, which binds cyanide and keeps it away from the electron transport chain of oxidative phosphorylation.
- thiosulfate binds cyanide, forming thiocyanate, which is renally excreted.
