OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How is blood supplied to the heart?

1. Through the pulmonary veins exclusively

2. By two coronary arteries branching from the base of the aorta

3. From the main vein of the body

4. By means of the lymphatic system

The correct answer is: By two coronary arteries branching from the base of the aorta

Blood is supplied to the heart primarily by two coronary arteries that branch off from the base of the aorta. When the heart pumps, it creates a pressure differential that allows oxygenated blood to flow from the aorta into these coronary arteries. These arteries are crucial for delivering oxygen-rich blood to the heart muscle itself, ensuring that it has the necessary nutrients and oxygen to function effectively. This vascular arrangement is vital because the heart requires a constant supply of oxygen to maintain its rhythm and function, much like any other organ in the body. If the coronary arteries become blocked or narrowed, it can lead to serious conditions such as angina or heart attacks. Other choices present less accurate mechanisms for heart supply. For instance, pulmonary veins carry oxygenated blood from the lungs to the left atrium, but they do not supply blood to the heart tissue itself. The main vein of the body refers to large veins like the vena cavae that return deoxygenated blood to the heart rather than supply blood to it. The lymphatic system plays a role in immune function and tissue fluid balance but does not supply blood to the heart or any other organ directly.