Characteristics of different types of hypoxia

[Akam ahz]

Hello,
My text book shows this diagram to explain characteristics of different types of hypoxia.

Arrows directed downward indicate a decrease and the arrows directed upwards indicate an elevation.

I know what each type is, but I don’t understand the above table. I can’t get an explanation of what happens to venous PO2 and venous O2 content in stagnant, anemic and histotoxic hypoxia.

Could someone give me explanation to the diagram?

Thanks in advance!

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[pretty_positron]

Let me take a crack at this.. I'm going to go row-by-row.

Arterial pO2 is normal for everything except hypoxic hypoxia (when there isn't enough oxygen in the environment, like in high altitudes) so that means for anemic, stagnant, and histotoxic you have a normal amount of oxygen in the environment.

For Anemic, you have a reduction in O2 content but you have a normal % saturation of Hb. This means that your Hb is working just fine, but there simply isn't enough Hb for a normal amount of O2 content.

Venous pO2, O2 content, and %sat of Hb is decreasing for anemic and stagnant but increasing for histotoxic.

Now, I know that venous pO2 always decreases because the O2 diffuses into tissues. So the pCO2 and pO2 equilibrate. If there's a decrease in venous pO2 then I would imagine pO2 < pCO2 but I may be wrong here.

So for stagnant, I believe the blood is moving slow (hence "stagnant") so a lot of diffusion is happening between the blood and the tissues.

For histotoxic, it's all going up. so I don't think there's any diffusion happening between the blood and the tissues.