Unformatted text preview: is not a simple linear one. The loading of hemoglobin with oxygen displays cooperative binding or positive feedback. Binding with O 2 molecules causes the Hb to change shape; this shape change facilitates additional O 2 binding. The oxyhemoglobin dissociation curve shows that at the P O2 found in the alveoli (about 104 mmHg), Hb is ~100% loaded. This can be restated as: hemoglobin leaves the lungs fully saturated with oxygen (4 O 2 /Hb). At the P O2 found in the tissues (about 40 mmHg), O 2 dissociates from Hb, but as can be seen from the graph, Hb is still 75% saturated. Only 25% of the O 2 dissociates from Hb at normal P O2 of tissues. Hb has released only one O 2 molecule and three more are theoretically available. This provides the blood and tissues with a reservoir of oxygen that can be released when needed. The metabolic needs of the body can change the unloading of O 2 ....
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- Fall '10
- Anatomy, Hemoglobin, oxyhemoglobin dissociation curve