Final answer:
Elastic arteries are large blood vessels close to the heart that can expand and recoil due to their high elastic fiber content. They play a key role in regulating blood pressure and maintaining steady blood flow. The transition from elastic to muscular arteries occurs as the vascular tree branches.
Step-by-step explanation:
An elastic artery, also known as a conducting artery, is a type of blood vessel that is especially adapted to withstand and utilize the high pressure of blood ejected from the heart. These arteries have thick walls with a high percentage of elastic fibers in all three layers, or tunics, allowing them to expand as blood is pumped through them by the ventricles, and then recoil when the blood surge has passed. This elasticity is crucial as it lowers the resistance to blood flow, prevents excessively high blood pressure, and aids in maintaining the pressure gradient necessary for blood circulation.
There is a gradual transition from elastic arteries to muscular arteries as the vascular tree branches, with muscular arteries containing more smooth muscle and less elastic tissue, primarily functioning in vasoconstriction. Elastic arteries are larger in diameter, typically greater than 10 mm, and their ability to stretch and recoil is essential for sustaining blood flow after the heart has pumped the blood, a characteristic felt when we sense our pulse.