Vessels with Muscle (image) University of Washington Caption The engineered microvessels can form bends and T-junctions. The blue dots are the nuclei of the endothelial cells in the vessel walls, and the cell junctions are red. When smooth muscle cells (green) are introduced, they wrap and tighten around the vessels like they do in the human body. Credit Y. Zheng, U. of Washington Usage Restrictions With credit. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.