A Level Biology Practice Exam

Which statement accurately describes the function of the arteries in relation to elastic recoil?

1. they become rigid under pressure

2. they maintain a constant large diameter

3. they contract and dilate minimally

4. they return to original shape after being stretched

The correct answer is: they return to original shape after being stretched

The function of arteries in relation to elastic recoil is accurately captured by the statement that they return to their original shape after being stretched. This characteristic is crucial for maintaining blood pressure and ensuring a continuous flow of blood throughout the circulatory system. When the heart pumps blood into the arteries during contraction (systole), the walls of the arteries expand to accommodate the surge of blood. This expansion is due to the elastic tissue within the arterial walls. Once the heart relaxes (diastole), the elasticity allows the arterial walls to recoil back to their original size. This recoil helps to maintain pressure in the arteries even when the heart is not actively pumping, which is essential for smooth and consistent blood flow. In summary, the ability of arteries to return to their original shape after being stretched is vital for their role in the circulatory system, ensuring that blood can move efficiently and with sufficient pressure.