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Gas Transport Via Circulation- Oxygen and Carbon Dioxide Transport By Blood. AT LUNG. -O 2 is dissolved in plasma (5% is transported this way. -This occurs between the alveolus of the lung and the capillaries surrounding them. Oxygen inflow. Oxygen reaches the capillaries.
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Gas Transport Via Circulation- Oxygen and Carbon Dioxide Transport By Blood
AT LUNG -O2 is dissolved in plasma (5% is transported this way. -This occurs between the alveolus of the lung and the capillaries surrounding them.
-O2 binds with Hb. - Hb is composed of a small globin protein (500 a.a) and a heme group (iron). The full name is hemoglobin. -this makes up 40% of the red blood cell (RBC).
-Each RBC has 300 M Hb molecules, and hence can carry over 1 Billion O2 molecules.
O2 + Hb HbO2 + CO2 - HbO2 = oxyhemoglobin - 95% is transported this way. - CO2 is released from the RBC to diffuse out of the blood into the lungs for exhalation.
Carbon Monoxide Poisoning: - hemoglobins affinity for CO (carbon monoxide) is 200X greater than it’s affinity for O2. - CO uses all of the hemoglobin sites, so there is none left to transport oxygen
AT THE BODY CELL From tissue into blood: • CO2 is dissolved in plasma (8% travels this way).
CO2 + H2O H2CO3 no enzyme • CO2 reacts with H20 to form H2CO3. This happens slowly because no enzyme is involved. *H2CO3 – Carbonic acid
3. CO2 + H20 H2CO3 Carbonic anhydrase enzyme From tissue to RBC -H2CO3 becomes H+ and HCO3- and moves into plasma. *HCO3 only leaves the RBC.
-carbonic anhydrase enzyme allows this reaction to occur 10 million times faster. - 72% of CO2 is transported this way.
CO2 + HbO2 HbCO2 - only about 20% moves this way. Note: bicarbonate ions (HCO3-) also buffer the blood. Ex. Control the acidity of the blood.