Final answer:
The right ventricle is the structure that receives blood from the right atrium and pumps deoxygenated blood into the pulmonary circulation to pick up oxygen.
Step-by-step explanation:
The structure that receives blood from the right atrium and pumps deoxygenated blood into the pulmonary circulation where it will pick up O2 is the right ventricle. The right atrium receives deoxygenated blood from the veins that come from the body, and it passes this blood to the right ventricle through the tricuspid valve. The right ventricle then pumps the deoxygenated blood into the pulmonary arteries which carry it to the lungs for oxygenation.