Carbon Dioxide Transport

CO2 is transported in blood in 3 forms;

• dissolved in plasma ( 7 -10%) as P c02

• chemically bound to hemoglobin (over 20%)

• Bicarbonate ions in plasma (70%)

• (HCO3-) in plasma

CO2 is transported in blood, occurring primarily in RBC’s. To reverse this -

Enzyme carbonic anhydrase reversibly and rapidly catalyzes this reaction

In systemic capillaries, after Hco3- is created -

Hco3- quickly diffuses from RBCs into plasma

Chloride shift -

after HCO3- is diffused from RBCs in plasma in systemic capillaries, outrush od HCO3- from RBCs is balanced as CL- moved into Rbcs from plasma

In pulmonary capillaries, everything happenes in reverse then from systemic capillaries

• HCO₃^– moves into RBCs while Cl⁻ moves out of RBCs back into plasma

• HCO₃^–  binds with H⁺ to form H₂CO₃

• H₂CO₃ is split by carbonic anhydrase into CO₂ and water

• CO₂ diffuses into alveoli

Haldane effect

he process by which oxygen affects how hemoglobin carries carbon dioxide (CO2)

-It's caused by the difference in how much CO2 binds to hemoglobin when it's oxygenated versus deoxygenated. 

Carbonic acid–bicarbonate buffer system:

helps blood resist changes in pH

Changes in respiratory rate and depth affect blood pH by -

• Slow, shallow breathing causes an increase in CO₂ in blood, resulting in a drop in pH 

• Rapid, deep breathing causes a decrease in CO₂ in blood, resulting in a rise in pH

hypoxia

• inadequate O₂ delivery to tissues; can result in cyanosis

hypoxia is caused by

• Anemic hypoxia: too few RBCs or abnormal or too little Hb

• Ischemic hypoxia: impaired or blocked blood circulation

• Hypoxemic hypoxia: abnormal ventilation; pulmonary disease, low levels of oxygen in air

• Carbon monoxide poisoning: especially from fire;  Hb has a 200◊ greater affinity for carbon monoxide than oxygen