Veins are made up of three layers of tissues and fibers:
- Tunica adventitia (outer layer): This layer provides structure and shape to the vein.
- Tunica media (middle layer): Composed of smooth muscle cells, this layer allows the vein to widen or narrow as blood flows through.
- Tunica intima (inner layer): This layer is lined with endothelium, a type of epithelial tissue that helps prevent blood clots from forming.
These layers work together to ensure that blood flows efficiently and smoothly through the veins, returning deoxygenated blood back to the heart.
