What Changes Occur in Blood Vessels During Systole?

The histological structure of blood vessels, particularly the arteries, also adapts during systole. Arteries have thick walls composed of three layers: the tunica intima, tunica media, and tunica adventitia. During systole, the following changes can be observed:

1. Elastic Fiber Stretching: The elastic fibers in the tunica media stretch to accommodate the increased blood volume ejected from the heart.
2. Smooth Muscle Contraction: The smooth muscle cells in the tunica media may contract to help regulate blood pressure and flow.
3. Endothelial Shear Stress: The inner lining of blood vessels, known as the endothelium, experiences increased shear stress, which can modulate the release of vasoactive substances.