RBC Wed Prereading Flashcards
List some major sources of iron
red meat, shellfish, fish-heme iron
enriched cereals, beans, tofu, seeds, potatoes, green veggies, dried fruit-non heme iron
When are plasma hepcidin levels high?
when stores are full of iron and erythropoietic activity is normal
What does high plasma hepcidin cuase?
downregulation of ferroportin and trapping of most of the absorbed iron
When are plasma hepcidin levels low?
when body iron stores are depleted or erythropoiesis is stimulated
What happens when hepcidin leves are low?
ferroportin activity increases, allowing a greater fraction of absorbed iron to be transferred into plasma transferrin
What protein allows for entry of non-heme iron?
DMT-1 divalent metal transporter 1
What protein allows for entry of heme?
heme transporter
What cofactor is required for the asorption of non-heme iron?
vitamin C
What enzyme reduces ferric to ferrous? What is it dependent on?
duodenal cytochrome B ascorbic acid (vit C)
What stores iron in dueodenal cells?
ferritin
What transports ferrous across the basal later membrane of duodenal cells?
ferroportin 1
What converts ferrous back to ferric once it has crossed the basal lateral membrane?
hephaestin
What molecule transports ferric in the blood?
transferrin
How do other cells take up ferric?
transferrin receptor–>endocytosis–>DMT1 to get out of endosome
What molecule regulates the release of iron from the duodenal epithelial cells?
hepcidin
