Quiz - 19 - Diving Knowledge Workbook - Diving Physiology

[Pedro Burrito]

From the Diving Physiology Section of the PADI Diving Knowledge Workbook Version 2.02 © PADI 2009:

Objective 2.6 - Explain the physiological effect of increased carbon monoxide levels (including cigarette smoking) on the diver and how they can be avoided.

Question 3

The symptoms of carbon monoxide poisoning are not as noticeable at depth because:

a. high levels of oxygen are dissolved in the plasma allowing tissues to meet their oxygen requirement.

b. high levels of nitrogen sedate the diver's central nervous system, slowing his/her metabolism.

c. lower levels of carbon dioxide help to counteract the effects of carbon monoxide.

d. lower levels of oxygen make the brain less sensitive and alert. ​

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Thank you for your patience while we try to give people something to discuss other than Covid-19 and/or Politics. I will post the answer covered by the spoiler tag later today.

 

[jonhall]

Three answers in so far and I'M IN THE MAJORITY!!!!

 

[Pedro Burrito]

Spoiler: Answer

a. high levels of oxygen are dissolved in the plasma allowing tissues to meet their oxygen requirement.

Remember that tissues receive oxygen in two ways. Primarily they are supplied by oxygen carried by the hemoglobin. But, they are also supplied by free oxygen dissolved in plasma. With the increased partial pressure at depth, the amount of oxygen in solution could be sufficient to provide the tissues' demand. The carbon monoxide would then have no noticeable effect. However, as the partial pressure drops during ascent, the oxygen in the hemoglobin will be needed. However, if the hemoglobin is locked-up by carbon monoxide, then insufficient oxygen will be delivered to the tissues.