RBC Physiology

Question 1

Function of RBC

Answer 1

Carry O2 from lungs to tissue and trasport CO2 from tissue to lungs and buffer H+

Question 2

Uniquie RBC properties

Answer 2

-Flexibility
-Strength
-Shape-> increased surface area
-Hemoglobin
-Lifespan-> short

Question 3

Deformability of RBC

Answer 3

-Structure of membrane and cytoskeleton
-High surface area to volume ratio
-Low viscosity cytoplasm

Question 4

RBC life span

Answer 4

Relatively short
-Horses have the longest with cats and dogs on the lower end

Question 5

Time for Erythropoiesis

Answer 5

5-7 days

Question 6

What stimulates erythropoiesis

Answer 6

Erythropoietin, produced from the kidney, stimulates stem cells in the bone marrow (spleen is minor) to erythroid precursors and continues to stimulate them to induce maturation.

Question 7

What triggers erythropoietin release

Answer 7

Hypoxia in the tissues (renal hypoxia specifically)
-Anemia
-Poor renal perfusion
-Poor oxygenation of blood (altitude)

Question 8

High EPO

Answer 8

Erythroid hyperplasia
-Shortened maturation time
-Accelerated release of reticulocytes
-increased Hgb synthesis in dividing cells
-Decreased apoptosis of progenitor cells

Question 9

Persistently low EPO

Answer 9

Erythroid hypoplasia
-Gradual onset of anemia
Could be from decreased functional renal tissue or inflammation

Question 10

Iron on erythropoiesis

Answer 10

A deficiency in iron results in anemia due to impaired RBC production

Question 11

Irons role in RBC

Answer 11

At center of heme molecule is Fe2+ which is what reversibly binds oxygen and this Hgb concentration is the rate limiting step in erythropoiesis

Question 12

MetHgb

Answer 12

Oxidized form (Fe3+) and lacks the electron pairs for O2 to bind

Question 13

CO and Hgb

Answer 13

Has a higher affinity to bind to Hgb than O2 and will displace

Question 14

Ferritin

Answer 14

Rapidly mobilized iron pool (KSU is the only lab that can measure this)

Question 15

Hemosiderin

Answer 15

Stable form of stored iron, aggregate of denatured ferritin and less readily available

Question 16

Heme synthesis

Answer 16

Occurs in RBC precursors and they need a mitochondria with AA synthase as a rate limiting enzyme and needs vitamin B

Question 17

Senescent RBC

Answer 17

Taken up by macrophages usually in the spleen and Hgb is degraded

Question 18

What happens to heme when RBC debraded

Answer 18

Made into bilirubin and then gets into the blood and bind to albumin until the liver-> Bu will leave the Alb and enters hepatocyte and binds to proteins to prevent from leaving-> now becomes conjugated to glucuronic acid (most species)-> enters canaliculus and into intestine-> bacterial degradation to Urobilinogen and recycled or degraded into stercobilinogen and excreted