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Multiple Choice
During normal circulation, hemoglobin is ______ saturated in blood entering the lungs?
A
about 98%
B
about 50%
C
completely (100%)
D
about 75%
Verified step by step guidance
1
Understand the role of hemoglobin in oxygen transport: Hemoglobin is a protein in red blood cells that binds oxygen in the lungs and releases it in tissues. Its saturation level depends on the partial pressure of oxygen in the blood.
Recall the concept of oxygen saturation: Oxygen saturation refers to the percentage of hemoglobin molecules bound to oxygen. In blood entering the lungs, oxygen levels are lower because oxygen has been delivered to tissues, reducing hemoglobin saturation.
Learn about typical saturation levels: Blood entering the lungs typically has a hemoglobin saturation of about 75%, as it has released oxygen to tissues during circulation.
Compare saturation levels: Blood leaving the lungs has a higher saturation (about 98%) due to oxygen binding in the lungs, while blood entering the lungs has a lower saturation (about 75%).
Conclude based on physiological principles: The correct answer is 'about 75%' because blood entering the lungs has already delivered oxygen to tissues, resulting in a lower saturation level compared to blood leaving the lungs.