Life and Death of RBCs Flashcards Preview

Week 23: Anemia > Life and Death of RBCs > Flashcards

Flashcards in Life and Death of RBCs Deck (16)
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1

Erythropoiesis

Production of the RBCs in bone marrow

2

Proerythroblast

First stage
Committed to becoming an RBC once it has receptors for EPO

3

Normoblast

Last nucleated stage of RBC formation

4

Reticulocyte

After expulsion of nucleus
Released from the bone marrow ~2 days later
Become a fully mature RBC about 24 hours after that

5

Erythropoietin

Glycoprotein hormone
Synthesized and secreted by the kidney (and a bit by the liver)
Increased when blood O2 concentrations fall
Essential cytokine for RBC precursors in marrow

6

2 reasons for the biconcave shape of RBCs

Maximizes surface area
Allows the hemoglobin to be close to the cell surface

7

2 functionally significant protein groups with the lipid bilayer

Integral membrane proteins
Peripheral membrane proteins

8

2 Integral membrane proteins and their functions

Glycophorin C: maintains RBC shape
Band 3: links plasma membrane to cytoskeleton
Both are critical to RBC shape and stability

9

3 Peripheral membrane proteins

Spectrin
Protein 4.2
Ankyrin

10

When does Hb synthesis occur?

Prior to nucleus extrusion

11

2 main proteins in Hb

Globin (2 beta and 2 alpha chains)
Heme (with Fe inside)

12

Heme groups

Covalently bound to globins
Fe in porphyrin ring
Fe reversible binds O2

13

Where does
1. CO2
2. CO
bind?

1. To the Hb protein chains
2. Competes with O2 for Fe

14

2 Major enzymatic pathways in the RBC

Pentose Phosphate Pathway
Glycolysis

15

Reduced glutathione

Prevents membrane lipid oxidation
Prevents globin oxidation and denaturation
Detoxifies oxidants

16

Pyruvate kinase

Key glycolytic enzyme
Tight regulation is really important for glycolysis and ATP production