Transcript CH 17 RBC Morphology

CH 17 – RBC Morphology
Erythrocytes
 >99% of the formed elements
 function to carry O2, CO2 & H+
 anatomy

biconcave disks, 8 µm in
diameter
 no nucleus
 limited metabolic activity
 ~280 million hemoglobin (Hgb)
molecules/cell



O2 carrying protein
synthesized in cytosol
before the nucleus is lost
33% of cell weight
Erythrocytes
 Bi-Concave disc shape

creates a higher surface
area/volume ratio increases gas
diffusion

very flexible structure allows
passage through capillaries

the smallest capillaries are no
wider than an RBC
Erythrocytes
 Normal Hgb in blood

Infants: 14-20g
Hgb/100ml

Adults:


Males: 14-15g Hgb
/100ml
Females: 12-15g
Hgb /100 ml
RBC’s (Electron Microscopy)
electron microscopy
Hemoglobin
Structure
 O2 combines with Hgb in lungs


O2 not very soluble in H2O
O2 needs a molecular transporter to carry it
 Hemoglobin




4 globin (protein) chains - 2 α chains & 2 β chains
4 non-protein heme pigments (lipid)
each heme pigment has iron ion (Fe²+) that carries 1 O2
each RBC can carry about 1 billion O2 molecules
 RBC's carry ~25% of the CO2 bound to Hgb - forms
carbaminohemoglobin
Erythrocyte (RBC) Life Span
 Life span


only 100-120 days
cannot repair damage due to loss of nucleus, ribosomes
 Old RBC’s destroyed in the spleen, liver and the bone marrow


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Macrophages phagocytize old worn RBC's
Breakdown products are recycled
Different pathways exist for each part of the Hgb molecule


globin chains - AA's used for other protein synthesis
heme
•
•
iron portion - Fe2+ recycled
non-iron lipid portion – converted to bilirubin - waste
– released into blood, secreted by the liver into bile
– bile enters intestine, is converted to urobilinogen by bacteria
– contributes to urine & feces color
RBC Life Span
End
RBC Morphology
CH 17