CARDIOVASCULAR SYSTEM 1. What is the function of the valves in the heart? 2. What is the function of the chordae tendineae? 3. The semilunar valves prevent backflow in the backflow into the The AV valves prevent 4. How does the operation of the semilunar valves differ from that of the AV valves? 5. Name the three vessels that drain blood into the right atrium. Is this blood oxygen rich or oxygen poor? 6. Name the vessels which drain blood into the left atrium. this blood oxygen rich or oxygen poor? Is 7. Distinguish between pulmonary and systemic circulation. 8. If the mitral (bicuspid) valve does not close properly, which circulation is affected (pulmonary or systemic)? 9. Why might a thrombus (blood clot) in the anterior descending branch of the left coronary artery cause sudden death? 10. Based on your observation of model and cadaver images, what differences do you observe between the right and left ventricles? 11. How do the structural differences between the right and left ventricles relate to the functioning of these chambers?
The Correct Answer and Explanation is :
Answers and Explanation
- What is the function of the valves in the heart?
The valves in the heart ensure unidirectional blood flow by preventing backflow as the heart contracts and relaxes. - What is the function of the chordae tendineae?
The chordae tendineae anchor the cusps of the atrioventricular (AV) valves to the papillary muscles, preventing the valves from inverting into the atria during ventricular contraction. - The semilunar valves prevent backflow into the…
…ventricles.
The AV valves prevent backflow into the…
…atria. - How does the operation of the semilunar valves differ from that of the AV valves?
The AV valves open during ventricular diastole to allow blood flow from the atria into the ventricles and close during systole to prevent backflow. Semilunar valves open during systole to allow blood to exit the ventricles into the arteries and close during diastole to prevent arterial blood from reentering the ventricles. - Name the three vessels that drain blood into the right atrium. Is this blood oxygen-rich or oxygen-poor?
The superior vena cava, inferior vena cava, and coronary sinus drain blood into the right atrium. This blood is oxygen-poor. - Name the vessels which drain blood into the left atrium. Is this blood oxygen-rich or oxygen-poor?
The pulmonary veins drain blood into the left atrium. This blood is oxygen-rich. - Distinguish between pulmonary and systemic circulation.
Pulmonary circulation carries oxygen-poor blood from the right ventricle to the lungs for oxygenation and returns oxygen-rich blood to the left atrium. Systemic circulation delivers oxygen-rich blood from the left ventricle to the body and returns oxygen-poor blood to the right atrium. - If the mitral (bicuspid) valve does not close properly, which circulation is affected (pulmonary or systemic)?
Pulmonary circulation is affected because improper closure can cause blood to backflow into the left atrium, leading to pulmonary congestion. - Why might a thrombus (blood clot) in the anterior descending branch of the left coronary artery cause sudden death?
This artery supplies a significant portion of the left ventricle, which pumps blood to the systemic circulation. A blockage can cause myocardial infarction (heart attack), impairing heart function and leading to sudden death. - Based on your observation of model and cadaver images, what differences do you observe between the right and left ventricles?
The left ventricle has thicker walls compared to the right ventricle. This is because the left ventricle pumps blood to the entire body, requiring greater force, whereas the right ventricle pumps blood to the lungs, which is a shorter distance. - How do the structural differences between the right and left ventricles relate to the functioning of these chambers?
The thicker walls of the left ventricle provide the necessary strength to generate higher pressure for systemic circulation. The thinner walls of the right ventricle are sufficient for the low-resistance pulmonary circulation.
Explanation (300 words)
The heart’s structure is intricately designed to ensure efficient blood flow and separation of oxygen-rich and oxygen-poor blood. Valves play a crucial role by maintaining unidirectional flow. AV valves (tricuspid and mitral) separate the atria from the ventricles, while semilunar valves (pulmonary and aortic) separate the ventricles from major arteries. Their operation is synchronized with the cardiac cycle to optimize efficiency. The chordae tendineae prevent valve prolapse, particularly during ventricular systole, safeguarding against regurgitation.
Blood flow in the heart follows distinct pathways. Oxygen-poor blood enters the right atrium through the superior and inferior vena cava and coronary sinus, while oxygen-rich blood from the lungs enters the left atrium via the pulmonary veins. Pulmonary circulation exchanges carbon dioxide for oxygen in the lungs, while systemic circulation delivers oxygen and nutrients to tissues and removes waste products.
Structural differences between ventricles align with functional demands. The left ventricle’s thicker walls generate the force needed for systemic circulation, while the right ventricle’s thinner walls suffice for the pulmonary circuit. A defect, such as mitral valve regurgitation, impacts pulmonary circulation, leading to symptoms like shortness of breath.
A blockage in the left coronary artery’s anterior descending branch can starve the left ventricle of oxygen, disrupting systemic circulation and causing life-threatening arrhythmias. This highlights the critical role of coronary circulation.
Understanding these relationships underscores the heart’s role as a highly efficient and vital organ.