4. Gas Transport and Erythrocyte Phys Flashcards
what is the fxn of blood
- deliver nutrients and O2
- remove waste products
- maintain homeostasis
- circulation
what is the normal level of hematocrit for women, men, newborn and 2 month old
women - 40%
men- 45%
newborn- 55%
2 month 35%
what are the fxn of erythrocytes
carrying O2 from lungs to body
carry CO2 from body to lungs
acid/base buffering
what are reticulocytes
precursors of erythrocytes
mature into erythrocytes entering circulation and these mature based on O2 demand
what is eryhtropoietin (EPO) and when is it produced
principle regulator
produced by kidneys in response to: anemia, low Hb, decreased RBF, central hypoxia (pul disease, altitude)
what regulates EPO
hypoxia inducible factor (HIF)
what happens to genetic deletion of HIF?
what about impaired regulations?
genetic deletion –> anemia, mutations in polycythemia
impaired regulation –> erythrocytosis
where do RBCs rupture
spleen, liver and bone marrow
When RBCs death and phagocytose - they break down into:
- globin –> AA –> reuse for protein synthesis
- heme –> Fe3+ bound to transferrin –> store in liver as ferritin –> recycle Fe3+ for more RBC formation
–> heme also converted to bilirubin –> liver –> SI –> kidney and Large intestine & excreted as urine and feces, respectively
how is O2 transported in blood
dissolved in plasma
bound to Hb (majority)
how do Hb and O2 bind
4 O2 molecules to 1 Hb
contain 4 heme sites - 2 alpha and 2 beta subunits for adults
what is normal O2 concentration
20 mL
15 g Hb/100 mL blood
what is the difference btn arterial and venous O2 saturation
arterial - 100 mm Hg - 97.5%
venous - 40 mm Hg - 75%
what are tissue PO2 levels and what do they mean
lower (steeper curve)
-O2 readily released from Hb to deliver O2 to tissue
what happens to O2 carrying capacity if Hb concentration decreases
O2 carrying capacity decreases (regardless the O2 saturation)
& vice versa
what is a left shift on the O2 dissociation curve
=increased affinity of Hb for O2
polycythemia & methemoglobinemia
what is right shift on a O2 dissociation curce
decreased affinity for Hb for O2 (advantage for unloading O2)
anemia, exercising, acidic, hypercarbic, 2,3 BPG
why does exercise favor a right shift
let go of O2 more –>
more to myoglobin for ETC, increase H+ concentration & hypercarbic
what does chronic hypoxia form
2,3 DPG
(2,3 DRG = end point of RBC metabolism)
what is required for erythropoiesis
adequate nutrition
Vit B12 & B9 (for DNA synthesis)
iron availability (absorption, transport and storage)
what do you get with folate or B12 deficient
megaloblastic macrocytic anemia
what occurs with poor B12 absorption
pernicious anemia
what do you get with iron deficiency
microcytic anemia
what do you get when you have deficient transport of transferrin to developing RBCs
hypochromic anemia
