Question

Figure shows schematic plant of blood circulation in humans with labels A to D. Identify the label and give
its function/s.

• A. A-Pulmonary vein-takes impure blood from body parts, $P{O}_2=60mmHg$
• B. B-Pulmonary artery – takes blood from heart to lungs, $P{O}_2=90mmHg$
• C. C-Vena Cava-takes blood from body parts to right auricle, $PC{O}_2=45mmHg$
• D. D-Dorsal aorta – takes blood from heart to body parts, $P{O}_2=95mmHg$

Answer 1

The correct option is C C-Vena Cava-takes blood from body parts to right auricle, $PC{O}_2=45mmHg$

Vena Cava takes blood from to body parts to right auricle. Partial pressure of $C{O}_2$ is 45 mmHg Hg under
which $C{O}_2$ is taken form tissues.

Human blood circulation is responsible for the transport of nutrients and oxygen to the different parts of the body. Oxygen-rich blood travels through the pulmonary vein and the left atrium into the left ventricle.

So, the partial pressure of oxygen will be very high. The pulmonary artery carries the deoxygenated blood from the right ventricle of the heart to the lungs.

Since, the blood is deoxygenated, the blood will have more partial pressure of carbon dioxide than oxygen. Aorta carries the oxygen rich blood from the left side of the heart to the body. The vena cava is responsible for carrying the doxygenated blood from the lower and middle parts of the body to the right atrium. The partial pressure of carbon dioxide in vena cava or veins is equal to 45 mm Hg. The partial pressure of oxygen in arterial blood is equal to 100 mm Hg.

So, the correct answer is option C.