Set 21 Flashcards
At what positive G force does visual “black-out” occur? Why does this occur?
Visual black out occurs at 4-6 G - forces blood to pool in abdomen and lungs, not enough blood to return to the heart, insufficient perfusion of the brain
The dorsal root ganglion is considered gray matter within the spinal cord. From what embryological derivative are the dorsal root ganglia derived? (
Neural crest (derviced from ectoderm)
A 40-year-old woman treated with lisinopril for stage I hypertension becomes pregnant. Why are ACE inhibitors contraindicated in pregnancy? What centrally acting α2-agonist is often used to treat hypertension in pregnancy?
ACEi/ARBS are teratogenic - 1st trimester they can cause cardiac and CNS malformations, 2nd/3rd they can cause renal problems
alpha-methyldopa
Which complement protein is an opsonin? Which complement protein aids in neutrophil chemotaxis? Which complement proteins form the membrane attack complex?
C3b = opsonin (C3b Binds Bacteria) C5a = neutrophil chemotaxis C5b-C9 = MAC
A 42-year-old obese man presents with a complaint of severe pain in his right knee. He believes he injured it while dancing at his cousin’s wedding last night. You suspect gout. How would you differentiate between gout and pseudogout upon exam of synovial fluid aspirate?
Gout - crystals are yellow when parallel to the light (negative birefringence), urate crystals are needle shaped
Pseudogout - crystals are blue when parallel to the light (positive birefringence), calcium pyrophosphate crystals are rhomboid shaped
An elderly patient fell and struck his head on a coffee table. His family brought him to the ER. He is currently conscious and at his neurological baseline. Non-contrast CT of the head reveals a crescent shaped radiopacity that follows the contour of the skull crossing suture lines. What type of intracranial hemorrhage might this be and which vessel(s) would be involved?
Subdural hematoma - rupture of bridging veins. Slow venous bleeding (less pressure). Seen in elderly, alcoholics, blunt trauma, shaken baby. Crescent-shaped hemorrhage that crosses suture lines. Midline shift. Cannot cross falx tentorium.
Where is most of the cerebrospinal fluid (CSF) generated? What is the function of CSF?
Most generated in choroid plexus in two lateral ventricles
FN: suspends the brain, homeostatic medium for regulation of pH and electrolytes, route for chemical messengers to be distributed in the nervous system
A child presents with nephritis, deafness and ocular dysfunction. What is the diagnosis? A gene defect in what type of collagen contributes to the dysfunctions associated with this syndrome? What type of collagen organizes bone, skin and tendons? What type of collagen organizes cartilage?
Alport syndrome
Type IV collagen
Bone, skin and tendon = Type I
Cartilage = Type II
A child is noticed to be yellow by a visiting relative, so he was brought to the clinic. His exam revealed jaundice and splenomegaly. The patient’s lab results reveal anemia and spherocytes. What test is used to confirm the diagnosis of hereditary spherocytosis? What findings are associated with hereditary spherocytosis?
Hereditary spherocytosis: defect in proteins interacting with RBC membrane skeleton and plasma membrane (Spectrin, Band 3, Protein 4.2 and Ankyrin). Less membrane causes small and round RBCs with no central pallor (increased MCHC, red cell distribution width) —> premature removal by the spleen
Findings: splenomegaly, aplastic crisis (parvovirus B19), negative coombs test (for antibody mediated hemolysis), gallstones
Test: positive osmotic frailty test, Eosin-5-maleimide binding test useful for screening
What is the composition of a nucleosome? Which histone ties nucleosomes together?
Basic packaging unit of DNA - DNA is wound twice around a core of histone proteins. Nucleosome core histones H2A, H2B, H3, H4 (each 2x) - Histone 1 is the only histone not in the core, it ties nucleosomes together. Histones are designed to bind to negatively charged DNA by having an abundance of positively charged amino acids Lysine and Arginine.
