Final answer:
True, both CvO2 and SvO2 decrease when cardiac output decreases, indicating reduced transportation of oxygen to body tissues.
Step-by-step explanation:
The statement 'CvO2 and SvO2 will decrease when CO decreases' is true. CvO2, or the concentration of oxygen in venous blood, and SvO2, the saturation of hemoglobin with oxygen in venous blood, are indicators of how much oxygen is being transported to the tissues.
When cardiac output (CO) decreases, there is less blood being pumped by the heart to the body tissues, which in turn leads to a reduction in the amount of oxygen that can be delivered and taken up by the tissues.
As a result, the oxygen extraction ratio increases, leading to a lower CvO2 and SvO2. These values are particularly relevant during physiological conditions such as exercise or illness when cardiac output can vary significantly.
In response to the multiple-choice question provided, the correct answer regarding changes in partial pressures as blood moves from arteries to veins is d. PO₂ drops and PCO₂ increases.
This is because tissues consume oxygen (PO₂) for metabolism and produce carbon dioxide (PCO₂) as a waste product, which diffuses into the blood.
Therefore, the partial pressure of oxygen decreases, and the partial pressure of carbon dioxide increases as blood transits from the arterial to the venous side within body tissues.
The correct answer to how PO₂ and PCO₂ change as blood passes from the arteries to the veins is d. PO₂ drops and PCO₂ increases.