4. All the following are true concerning the chambers and vessels of the heart, except? a. Ventricles are discharging chambers of the heart. b. Left ventricle pumps blood into the pulmonary trunk. c. Right ventricle has walls three times thicker than the wall of the left ventricle. d. Blood enters the right atrium by the inferior vena cava, superior vena cava, and the coronary sinus. 5. Following the flow of blood through the heart, freshly oxygenated blood from the lungs is first received by the a. left atrium. b. right atrium. c. left ventricle. d. right ventricle.

Did you know that the design of the heart is primarily an evolutionary masterpiece? The heart evolved to efficiently handle the demands of oxygen delivery in a complex organism. The left ventricle is notably thicker than the right because it needs to pump blood throughout the entire body, unlike the right ventricle, which only delivers blood to the lungs. This clever adaptation illustrates how our bodies have evolved to maximize efficiency! When it comes to blood flow, there's a sequence to the heart's rhythm that makes it a true powerhouse! Freshly oxygenated blood from the lungs enters the heart through the pulmonary veins and is first received by the left atrium. From there, it flows into the left ventricle, ready to be sent out to the body. Remember this sequence, and you'll have a solid understanding of the heart's operation!