Red Blood Cells Flashcards
How is CO2 transported in the blood?
Converting it into freely soluble HCO3- via carbonic anhydrase
How are fatty acids transported in the blood?
Serum albumin
How are triglycerides transported in the blood?
Lipoproteins
What are the formed elements of blood?
Sedimenting portions RBCs Platelets WBCs
What is the major protein in blood?
Albumin
What are the major cellular components of blood?
RBCS then platelets then WBCs
What does a mature erythrocyte NOT contain?
Nucleus Ribosomes Mitochondria
What causes RBC crenation?
Depletion of ATP
What causes RBCs to be called echinocytes?
Entry of large amounts of calcium ions resulting in a spiky appearance.
What causes RBCs to be called spherocytes?
Loss of spectrin scaffolding results in a spherical shape
How do RBCs make ATP?
Anaerobic glycolysis
What metabolic processes do RBCs need ATP for?
Maintenance of Ca levels Maintenance of Na/K gradients Creation of 2,3-DPG
How do 2,3-DPG levels affect RBCs?
Affects the binding of oxygen to hgb
Describe the role of Methemoglobin reductase (aka diaphorase)
An enzyme that reduces ferric (Fe3+) methemoglobin to Fe2+ with the help of NADH as a cofactor
What forms as a result of an accumulation of denatured methemoglobin?
Heinz bodies
What does reduced glutathione (GSH) do? What maintains its reduced state?
Protect the cell from oxidants (esp H2O2) Maintained by NADPH + G6PD (enzyme)
In a healthy person, what percentage of circulating RBCs are reticulocytes? How is this value used clinically?
2%, Reticulocyte index used to diagnose anemia
What physiologic level stimulates erythropoietin production?
Low tissue pO2 and low pH
Describe heme.
A porphyrin ring structure containing iron which binds oxygen.