The aorta

This is an image of the aorta at low magnification. I apoligize for the low resolution of the image. The resolution of the magnifications are higher tough, so you'll be able to see more details.

The aorta is the largest artery in the human body, originating from the left ventricle of the heart and branching into smaller arteries to supply oxygenated blood to the body's tissues. The aorta is about the diameter of a garden hose in adults, but it can stretch up to twice its normal size when subjected to high pressure. Some animals have unique adaptations in their aortas, such as the giraffe, which has a very thick and elastic aorta to accommodate the high pressure generated by its long neck.

The human aorta is also of the elastic type (not muscular) even though we don't have a very long neck.