Study Guide: Chapter 13 (2) Flashcards
What are the stages of development for RBCs?
1) Erythroblast in bone marrow
2) Reticulocyte (within 24 hours in circulation, lacks a nucleus, but still has other organelles)
3) Mature RBC (after 24 hours in circulation, no organelles)
A hormone-like erythrocyte-stimulating signal that travels to the bone MA to stimulate
RBC formation
erythropoietin
Which organ senses low oxygen in arteries to stimulate erythropoiesis?
Kidneys
What form must iron be in to bind O2 in the lungs?
ferrous form
What are the steps in hemoglobin formation?
1) Heme (iron + porphyrin ring )made in mitochondria
2) Heme associates with a globin protein chain made by ribosomes in the cytoplasm
3) 4 heme/globin units aggregate to form one hemoglobin
4) RBC is packed with hemoglobin units.
iron + porphyrin ring made in mitochondria
heme
Where are worn out red blood cells removed from circulation and degraded?
spleen
What is recycled when RBCs are degraded in spleen?
1) Iron
2) Globin amino acids
What is not saved when worn RBCs are degraded in the spleen?
porphyrin ring (excreted by the liver as bile pigment)
What kind of hemoglobin makes up 98% of the adult hemoglobin in the body?
HbA (consists of 2 alpha and 2 beta globin chains)
What hormone, released by the kidneys when O2 in arterial blood is low, stimulates RBC formation in bone marrow?
erythropoietin
What two conditions cause hemoglobin to not be able to transport O2 well to tissues?
1) CO exposure (CO binds 200x better to heme iron than O2)
2) Heme iron is oxidized to metHb which cannot carry O2
How do you treat CO exposure?
Highly concentrated O2 to outcompete CO
How do you treat oxidized metHb?
Treat with agent (such as methylene blue) to reduce oxidized heme iron.
