RBC Destruction Flashcards
an increased rate of RBC destruction; premature RBC destruction
hemolytic disorder
hemolytic anemia occurs when…
rate of RBC destruction exceeds rate of RBC production
RBC survival is dependent on three things:
- RBC membrane
- Hb structure and function
- RBC metabolic pathways
T or F. 1% of RBCs are removed daily
True!
- most done by macrophages in mononuclear phagocyte system (extravascular hemolysis)
AKA macrophage-mediated hemolysis
extravascular hemolysis
Describe extravascular hemolysis
- RBCs => red pulp of spleen; senescent RBCs trapped there + ingested
> low glucose in spleen
> deteriorating glycolytic process = decreased ATP production
> membrane systems fail = no more selective permeability; water enters => spheres - ingested by macs in spleen/liver
- Hb = globin + heme (iron + protoporphyrin)
- AAs from globin and Fe are recycled
- protoporphyrin = bilirubin excreted
T pr F. Ferritin picks up old iron from spleen/liver and goes back to pool or RBC precursor
F, transferrin
This breaks down heme to biliverdin
heme oxygenase
= biliverdin reductase converts biliverdin to unconjugated bilirubin
= bilirubin becomes conjugated (soluble) with glucuronic acid
= conj. bil .goes to the intestine via bile
- gut bacteria converts this to urobilinogen
- > excreted into stool
RBCs breaking down in circulation, causing cell fragmentation
intravascular hemolysis
This system aids in salvaging iron and AAs when intravascular hemolysis occurs
haptoglobin-hemopexin-methemalbumin system
when free dimers accumulate in plasma
hemoglobinemia
when free dimers are filtered through the kidneys
hemoglobinuria
Some Fe gets reabsorbed by renal tubular cells and stored as this after intravascular hemolysis
Hemosiderin
Features of intravascular hemolysis
- jaundice
- splenomegaly
- gallstones
- brown urine
- signs of anemia: fatigues, dyspnew, dizziness, pallor, tachycardia
an increase in unconjugated plasma bilirubin gives yellow colour to the skin and sclera
jaundice
