Lastly, is an outer layer of connective tissue called the adventitia. The vaginal wall has three layers&colon; tunica mucosa, muscularis, adventitia. The outermost layer is the adventitia that consists of fibrous tissue. The healthy epicardial coronary artery consists of three layers, the tunica intima, media, and adventitia. Other more muscular parts are lined with adventitia. Beyond these layers sits an adventitia containing blood vessels, lymphatic vessels, and veins. The adventitia, () is the outer layer of fibrous connective tissue surrounding an organ. In addition, the oral cavity has adventitia.