PHSI 208 Lecture 41: M15 Respiratory System 2-3
Document Summary
Importance of removing co2 from the body: elevated pco2 causes acidosis, low ph leads to interruptions in hydrogen bonds and denaturing of proteins, abnormally high pco2 depresses the cns causing confusion, coma or even death. Although very soluble, cells produce far more co2 than plasma is capable of carrying: only about 7% of co2 carried by venous blood is dissolved in plasma. Remaining 93% diffuses into rbc"s: 23% binds to hemoglobin hbco2 (carbaminohemoglobin, 70% is converted to hco3. Co2 is transported in 3 ways: dissolved in plasma (7%, bound to hemoglobin (23%), forming carbaminohemoglobin, converted to bicarbonate, hco3. Tissues have pco2 > 46 mmhg while the systemic capillaries have pco2 40 mmhg, the pressure gradient allows the co2 to diffuse out of cells and into the plasma. Some will dissolve in the plasma (7%), some will diffuse into the rbc (93%) Is moved to the plasma in exchange for cl- (the chloride shift, to retain neutrality within the rbc)
