07 CO 2

Transportation

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• CO2 stored as HCO3 to be transported to lungs

Bohr Effect

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• conversion produces H+ ion that binds to globin chain to form HHb

• instead of dropping from 100 to 75% at tissue PO2 50 mmHg, drop to 50%, better unloading

• Bohr effect helps unload O2 via H ion binding to Hb

Cl Shift

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• high bicarb inside cell diffuse out, in exchange for Cl

Haldane

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• x: level of CO2

• y: amount CO2 bound to Hb

• purple line: normally, more PCO2 in blood = more bound to Hb

• in reality, blue line: even more bound to Hb at low O2 level

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• Bohr for O2

High Altitude

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• small box: someone living at high altitude

• mild polycythemia

Exercise

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• arterial side maintain normal rate: not hypoxic or hypercapnea

Cerebral blood flow

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• cerebral vasodilator

• left, O2: at normal range, O2 does not change cerebral blood flow much

• right, CO2: at normal range, powerful effect on blood flow

Breathing

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• CO2 in blood stream major stimulus, not O2

• PNS chemoreceptor: only kick in under severe hypoxia, normally CNS working

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• hypoxemia stimulate respiratory rate, can get low with O2 = high CO2, confusion

• in hospital on ventilation, O2 can make O2 saturation high and mask hypoventilation

• put on ventilator

• hypo ventilating, CNS symptoms