Large Vein Total Magnification: 200X Objective: 20X N: Nucleus SM: Smooth Muscle CF: Collagen Fiber TI: Tunica Intima TM: Tunica Media TA: Tunica Adventitia Lab: Lab 5 Circulatory system and blood Comments Is the lumen of this blood Is the lumen of this blood vessel on the top or the bottom. If the top, then your labels are correct. If the bottom, then they're not. Can you label the lumen so it's clear what you are showing? Also, the label for smooth muscle would be better if it were pointing to the tunica media layer. The tunica media is a few layers of smooth muscle, while the tunica adventitia is more connective tissue.