Lipid-Soluble Vitamins (Kaplan) Flashcards
How does PTH increase the amount of vitamin D?
induces synthesis of 1-α-hydroxylase in the proximal tubule of the kidney
What is the effect of vitamin D on phosphate?
Increases (re)absorption in the intestine and kidney.
What is the difference between metastatic and dystrophic calcification?
Metastaic is generalized and due to high serum Ca++. Dystrophic is localized and d/t tissue degeneration.
What is the effect of vitamin A deficiency on the lungs?
Keratinized squamous metaplasia. increased infections
What are the Sx of Vit A toxicity?
Brittle nails, diarrhea, excessive sweating, increased intracerebral pressure.
What is the pathway of neurotransmission from the rod cell to the optic nerve?
Glutamate release from rod cell -> GABA release from bipolar cell -> inhibition of optic n.
Does the rod cell need to be depolarized or hyperpolarized to stimulate the optic nerve?
hyperpolarized
What type of receptor is rhodopsin?
G-protein-coupled
Please provide the steps for rod cell hyperpolarization following a photon hitting rhodopsin.
trans-retinal to cis-retinal -> Gt protein activates cGMP phosphodiesterase -> cGMP deactivated -> ligand-gated Na+ channel closes
What diseases are Auer rods found in?
AML M2 and M3
What is the danger posed by Auer rods?
They are lysosomal enzymes, and when released may cause DIC.
What are the lab values for coagulation/clotting in vit K def/warfarin?
bleeding time normal (plt’s clot); PT prolonged (Ca++ can’t bind clotting factors)
What are the lab values for coagulation/clotting in vit C def?
prolonged bleeding time (plt-vWF ccan’t bind to collagen); PT normal
What are the main Sx of vit E deficiency?
Hemolytic anemia acanthocytosis ataxia peripheral neuropathy retinitis pigmentosum
