B ) it’s increase in cytosol allows muscle shortening due to the formation of bridges between actin and myosin
Answer:
The best answer to the question: The stress-relaxation effect occurs in all blood vessels but is most important in the arteries, would be, B: False.
Explanation:
The reason for this being the correct answer comes from the function that both arteries and other blood vessels play and the significance of the process of stress-relaxation to the functionality of oxygenation, blood flow and pressure.
Stress-relaxation is the process by which the pressure within a specific tissue, in this case the blood vessels, does not increase as the volume of blood increases. Now, because arteries´ main job is not merely to conduct oxygenated blood from the heart towards the tissues of the body, it requires the presence not just of volume, but also of pressure, and usually, pressure in arteries is higher than the actual volume of blood. This is possible because of the high content of muscular tissue present in the middle layer of arteries. Without this high pressure, exchanges would not be possible. But veins, whose main purpose is to return all the de-oxygenated blood from the tissues to the heart, have the need to become reservoirs of large volumes of blood, and therefore have what is known as a high level of compliance (their muscular layer is not as powerful as that of arteries and the elastic tissues are more prominent, allowing the vessel to contain larger volumes of blood, but exert much lesser pressure). It is these blood vessels, veins, who show a high level of stress-relaxation, contain volume without affecting pressure, and not arteries, and that is why the answer is false.
