Chapter 2 - Erythropoiesis And Hemoglobin synthesis Flashcards
What is a erythropoieses?
Production of red blood cells
What is the primary function of red blood cells?
To carry hemoglobin which is responsible for the transportation of oxygen and carbon dioxide within the body
Red blood cells maintain hemoglobin and it’s functional Ferrous state by a series of metabolic reactions
What is erythropoietin?
A hormone which initiates the production of red blood cells in the bone marrow it is produced in the kidney.
Where are red blood cells formed?
Bone marrow
What are the stages of maturation in the red blood cell?
Rubriblast (pronormoblast) Prorubricyte (basophilic normoblast) Rubricyte (polychromatic normoblast) Metarubricyte (orthochromic normoblast) Reticulocyte Mature erythrocyte
What are some characteristics of a Rubriblast (pronormoblast)
18 to 20 µm
N:C ratio of 6 to 1
Dark marine blue cytoplasm
Beginning to accumulate components necessary for hemoglobin production
What are some characteristics of a Prorubricyte (basophilic normoblast)
16 µm
N:C Ratio of 6 to 1
No nucleoli red to purple chromatin
What are some characteristics of a Rubricyte (polychromatic normoblast)
13 µm N:C of 4 to 1 nuclear chromatin is condensed and compacted hemoglobin begins to be synthesized last stage capable of mitosis
What are some characteristics of a Metarubricyte (orthochromic normoblast?
8 µm N:C ratio of 1 to 1
nuclear chromatin is homogeneous (pyknotic)
What are some characteristics of a Reticulocyte?
8 µm
no nucleus
remnants of RNA visualized as reticulum RNA remnants will continue to form Heme
Hemoglobin production is completed here
slightly larger than mature red blood cell when it’s released in peripheral blood called Polychromatophilic
What are some characteristics of an erythrocyte?
6 to 8 µm no nucleus biconcave disc shape does not produce hemoglobin lives approximately 120 days
If there is an increased demand for oxygen carrying capacity what is released into the blood?
Reticulocytes
When does hemoglobin synthesis start and end?
it starts in the polychromatophilic normoblast (rubricyte)stage and ends in the reticulocyte stage
True or false hemoglobin is a complex protein?
True it is composed of a heme portion and a protein globin portion
Where does the synthesis of heme take place?
In the mitochondria of an immature red cell
Where does the synthesis of globin take place?
In the ribosomes of an immature red cell
What does a hemoglobin molecule consist of
Four gene groups and four polypeptide chains
What Percent of the dry weight of the red cell is hemoglobin?
90%
Hemoglobin a
hemoglobin F
hemoglobin A2 consist of what?
2 Alpha, 2beta chains
2 Alpha, 2 gamma chains
2alpha, 2 Delta chains
Where do red blood cells get their energy from?
The breakdown of glucose (glycolysis)
The M den-Mayerhoff pathway provides 90% of what?
ATP
The phosphogluconate pathway produces how much ATP?
5 to 10%
The methemoglobin reductase pathway As a responsible for what?
Maintaining iron in the reduced ferrous state so O2 can be delivered to the tissues
What does the heme portion contain?
Four iron atoms in the Ferrous state
