Kaplan Nursing Entrance Practice Exam

What are the two main types of chambers in vertebrate hearts?

1. Atria and ventricles

2. Aorta and vena cava

3. Arteries and veins

4. Atria and veins

The correct answer is: Atria and ventricles

The two main types of chambers in vertebrate hearts are the atria and ventricles. The atria are the upper chambers of the heart that receive blood from the body and lungs. They function to collect blood and pump it into the ventricles, which are the lower chambers responsible for pumping blood out of the heart to the lungs and the rest of the body. This division into atria and ventricles is significant because it allows for a more efficient separation of oxygenated and deoxygenated blood, particularly in more complex vertebrates with double circulatory systems, such as mammals and birds. This separation is vital for maintaining effective blood circulation and ensuring that oxygen-rich blood is efficiently delivered to tissues while returning oxygen-poor blood to the lungs for reoxygenation. In contrast, the other options refer to components or categories unrelated to the structural classification of heart chambers. The aorta and vena cava are major blood vessels connected to the heart, while arteries and veins are types of blood vessels. Atria and veins mix terms incorrectly, as veins are not chambers but vessels that carry blood to the heart. Hence, the correct terms specifically describing the heart's internal structure are indeed atria and ventricles.