TransferrinandFerritinTf-FellgbindingtoTfR-Fe()Receptor-mediatedPlasmaTfR-(pH7.2)endocytosismembraneSOClathrin-coatedpitRecyclingendosomeSTEAPDMTOTFe(u)Fe0Oreln(pH5.5)Fe(ll)-VEndosomeTransferrin:proteinto caryFe3+Ferritin:Storagefor Fe2+老烩餐FeFe祥FeFeSTEAP3:anendosomalreductaseTFerritinHaemoglobinDMT1:divalentmetaltransporter-1NatureReviews|Molecular Cell Biology
Transferrin and Ferritin Transferrin: protein to carry Fe3+ Ferritin: Storage for Fe2+ STEAP3: an endosomal reductase DMT1: divalent metal transporter-1
Recycling the Components ofAgedorDamagedErythrocytesErythrocytes form in red bonemarrow.Erythrocytemembrane proteinsandglobinproteins are broken down into amino acids,someofwhichareused lomakenewerythrocytes.Erythrocytes circulate inbloodstreamfor120days.Hemecomponentsofbloodarerecycled.Heme(minus iron)(iron ions)HemeiscomvertedintobiliverdinandIronistransportedinthen tobilirubin.thebloodbytheproteinwhichissecretedtransteinand storedSpleenLiverinbilefromthe liver.bytheprotein ferritinin the liver.Agoderythrocytes are phagocytizedintheliverandspleen
DestructionofRBCsFe2+transported in circulationBONEOld,damagedRBCsengulfedbymacrophagesFe2+MARROWbytransferrinMACROPHAGE-AminoRBCacidsformationHemeBLOODPLASMANewRBCsBiliverdin120-dayRemainingironrecycledhemereleasedintoaveragecirculationlifespanBilirubin90%OldandMacrophages10%Becomebilirubindamagedin spleen, liver,HemolysisRBCSbonemarrow中具Goesto the liverKIDNEYS具HbBilirubinBilirubin secreted in bile (turnsbileyellow)BilirubinBilirubin-derived具productsLIVERBile enters the intestineAbsorbedintoExcretedEliminatedthe circulationinblleinurine果Bilirubin-derivedUrobilinsSMALLproductsStercobilinsBilirubinINTESTINEConverts to urobilinogenEliminatedLARGEINTESTINEinfecesExcretedinfeces(turnsfecesbrown)
Destruction of RBCs
FeedbackControlofRBCProductionSomestimulusdisruptshomeostasisbyLow O2Decreasing人Oxygendeliverytokid-neys (andothertissues)Kidneyreleases erythropoietin人ReceptorsKidneycellsdetectlowerythropoiesis in the red bone marrowoxygenlevelInputIncreased erythropoietinsecreted intobloodControl centerReturntohomeostasisRBCs are releasedProerythroblasts inwhenoxygendeliveryredbonemarrowtokidneysincreasesmaturemorequicklytonormalintoreticulocytesOutputMore reticulocytesentercirculating blood(100 to 120 days later)EffectorsLargernumberofRBCsin?circulationOld, damagedRBCs engulfed by macrophagesIncreasedoxygendeliverytotissues
Feedback Control of RBC Production
What Is Anemia?Anemiaisaconditionthatdevelopswhenyourbloodlacksenoughhealthyreobloodcellsorhemoglobin.Hemoglobinisamainpartof redbloodcellsandbinds oxygen.If youhavetoofeworabnormal redblood cells,oryourhemoglobinisabnormal orlow,thecellsinyourbodywill notgetenoughO21.RBCnumberandquality2.Hbnumberandquality3.OrbothRBCandHbThereare 4ootypesofanemia,butthemost commontypesare.Iron-deficiency anemia.Pernicious anemia·Aplasticanemia·Sickle Cellanemia.Trauma related anemia
1. RBC number and quality 2. Hb number and quality 3. Or both RBC and Hb