$$\mathrm{HbO}_2\% = \frac{[O_2$]}{[O_2$] + P_{50}} \times 100$$

Question 1

On the oxygen-hemoglobin dissociation curve, where would the lungs most likely be represented?

Accepted Answer

At the region where $$\mathrm{PO}_2 is $$around 100 mmHg and hemoglobin is nearly fully saturated

Question 2

Which part of the oxygen-hemoglobin dissociation curve best represents resting tissues?

Accepted Answer

Where $$\mathrm{PO}_2 is $$approximately 40 mmHg and hemoglobin saturation is about 75%

Question 3

Active tissues are represented on the oxygen-hemoglobin dissociation curve at which $$\mathrm{PO}_2$$ value?

Accepted Answer

At $$\mathrm{PO}_2$$ values below 40 mmHg, where hemoglobin saturation drops rapidly

Question 4

What happens to hemoglobin saturation as $$\mathrm{PO}_2$$ increases above 50 mmHg?

Accepted Answer

Hemoglobin saturation approaches 100% and changes very little with further increases in $$\mathrm{PO}_2$$

Question 5

Why does hemoglobin release more oxygen in active tissues compared to resting tissues?

Accepted Answer

Active tissues have lower $$\mathrm{PO}_2$$, causing hemoglobin to release oxygen more readily due to the steep part of the dissociation curve

Question 6

Which physiological condition would shift the oxygen-hemoglobin dissociation curve to the right?

Accepted Answer

Increased $$\mathrm{CO}_2$$, increased temperature, and decreased pH (Bohr effect)

Question 7

If a patient is experiencing hypoxia, which part of the oxygen-hemoglobin dissociation curve is most relevant?

Accepted Answer

The steep portion between 20 mmHg and 50 mmHg, where small changes in $$\mathrm{PO}_2$$ cause large changes in saturation

Question 8

Which equation best describes the relationship between oxygen partial pressure and hemoglobin saturation?

Accepted Answer

$$\mathrm{HbO}_2\% = \frac{[O_2$]}{[O_2$] + P_{50}} 	imes 100$$

Question 9

A patient with a fever is likely to have a hemoglobin dissociation curve that is:

Accepted Answer

Shifted to the right, promoting oxygen release to tissues

Question 10

During intense exercise, what happens to the $$\mathrm{PO}_2 in $$active muscle tissues and how does this affect hemoglobin saturation?

Accepted Answer

$$\mathrm{PO}_2$$ decreases, causing hemoglobin saturation to drop and more oxygen to be released

Question 11

Which of the following best explains the plateau phase of the oxygen-hemoglobin dissociation curve above 50 mmHg?

Accepted Answer

Hemoglobin is nearly fully saturated, so further increases in $$\mathrm{PO}_2$$ have little effect on saturation

Question 12

If a tissue has a $$\mathrm{PO}_2 of 30 $$mmHg, what is the expected hemoglobin saturation?

Accepted Answer

Approximately 60%

Question 13

Why is the steep portion of the oxygen-hemoglobin dissociation curve physiologically important?

Accepted Answer

It allows hemoglobin to release large amounts of oxygen in response to small decreases in $$\mathrm{PO}_2$$

Question 14

Which factor does NOT cause a rightward shift in the oxygen-hemoglobin dissociation curve?

Accepted Answer

Decreased temperature

Question 15

A patient with chronic lung disease has a $$\mathrm{PO}_2 of 55 $$mmHg. What is the expected effect on hemoglobin saturation?

Accepted Answer

Hemoglobin saturation will be lower than normal, around 88%

Hemoglobin Oxygen Dissociation Curve: Saturation and Physiological Context

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