Question

Choose the correct answer from the alternatives given.
In an one-circuit circulatory system, blood pressure:

• A. cannot be determined
• B. is higher at the intestinal capillaries than at the gill capillaries
• C. drops significantly after gas exchange has taken place
• D. is constant throughout the system

Answer 1

The correct option is C drops significantly after gas exchange has taken place

In a single-circuit circulatory system as seen in fishes, the oxygenated blood from the gills does not enter the heart. The heart does not receive oxygenated blood, so known as venous heart. It is directly distributed in the entire body, after which it loses its pressure due to the absence of pushing force. Only the deoxygenated blood enters the auricle and then the ventricle. The deoxygenated blood enters the gills for oxygenation from the ventricle. Blood has a slow flow and low pressure.

So, the correct option is 'drops significantly after the gas exchange has taken place'.