to carry oxygen bound to hemoglobin to tissues and carry CO2 to lungs for excretion
What do RBCs convert CO2 into?
Where are RBCs produced?
in the bone marrow
What is hematopoiesis?
production of blood cells
What is erythropoiesis?
production of RBCs
What is extramedullary hematopoiesis?
hematopoiesis that takes place outside the bone marrow (often in spleen or liver)
Extramedullary hematopoiesis can be in response to what?
severe anemia or other pathological condition such as neoplasia
What can a pluripotent stem cell become?
depending on various cytokines and hormones, they can become RBCs, granulocytes, platelets or lymphocytes
What is the main factor in production of RBCs?
What is erythropoietin produced by?
the fetal liver and adult kidney
Renal peritubular cells produce erythropoietin in response to what?
What is the shape of RBCs in: - most mammals? - camelids? - birds, reptiles, amphibians and fish?
mammals - biconcave disc camelids - ovoid birds, reptiles, amphibians and fish - nucleated ovoid
Which RBCs have a higher Hb concentration?
What does a biconcave disc shaped RBC allow for?
bending of RBC when passing through capillaries
What is hemoglobin?
the major molecule in RBCs that carries oxygen bound to iron
Where is hemoglobin produced?
in the bone marrow while RBC is nucleated and for short time after release as a reticulocyte
Where is most of the iron in the body present?
in Hb in RBCs
Some iron is present bound to transport proteins in the blood such as what?
When iron is stored in the liver, bone marrow and spleen what is it known as?
Iron can only be lost by how?
What is the main pathway for RBC destruction?
extravascular destruction; hemoglobin is split into heme and globin; globin is broken down in AAs for recycling; iron is split from heme molecule; heme is broken down by heme oxygenase to CO and biliverdin; biliverdin is reduced to bilirubin; bilirubin is bound to albumin for transport to the liver; bilirubin is conjugated to glucuronic acid and excreted into the bile; small amounts of unconjugated bilirubin can be excreted by the kidney
Why do bruises turn to yellow?
because of the bilirubin due to hemoglobin breakdown
Which animal lacks biliverdin reductase?
birds (this is why they develop green discoloration as hemoglobin is broken down in bruises)
What is the minor pathway for RBC destruction?
intravascular lysis of aged RBCs; plasma protein haptoglobin binds hemoglobin for transport to the liver and hemoglobin's fate is the same as for extravascular destruction
Abnormalities in size of RBCs: -anisocytosis? -macrocytosis? -microcytosis?
anisocytosis: variation in sizes macrocytosis: larger than normal microcytosis: smaller than normal
Abnormalities in color of RBCs: -polychromasia? -hypochromasia?