Question

21. Low blood levels of O2 augment chemoreceptor sensitivity to pCO2. How would a low pO2 effect respiratory rate?

It would decrease respiratory rate

It would increase respiratory rate

22. Which of the following describes the "hypercapnic drive"

CO2dictates respiratory rate by being converted to HCO3- in the cerebrospinal fluid. H+ stimulate the I neurons to fire at a rate that dictates respiratory rate

CO2 indirectly dictates respiratory rate by being converted to H+ in the cerebrospinal fluid. H+ stimulate the I neurons to fire at a rate that dictates respiratory rate.

CO2 dictates respiratory rate by stimulating I neurons

23. Breathing 100% oxygen will:

Increase pO2 and the rate of oxygen unloading at the tissues

Significantly increase oxyhemoglobin saturation

Cause a right shift in the oxygen-hemoglobin dissociation curve

24. All of the following play a role in increasing the oxygen unloading at tissue in someone with iron deficiency anemia EXCEPT:

An increase in 2-3 DPG

The affinity of 2-3 DPG for hemoglobin

An increase in deoxyhemoglobin

Respiratory acidosis

Answer 1

21. It would increase respiratory rate

o22. CO2 dictates respiratory rate by being converted to HCO3- in the cerebrospinal fluid. H+ stimulate the I neurons to fire at a rate that dictates respiratory rate

Explanation - The central chemoreceptors are sensitive to change in H+ ion concentration. Change in CO2 is percived as change in H+ ion by converting CO2 to HCO3- & H+. This H+ diffuses across blood brain barrier and stimulate the central chemoreceptor and hence dictates the respiratory rate.

23. Increase pO2 and the rate of oxygen unloading at the tissues

When we breath 100% Oxygen, more and more oxygen is dissolved in the blood and it increases the partial pressure of oxygen in the blood and also helps in unloading more oxygen to the tissue.

24. The affinity of 2-3 DPG for hemoglobin