Structure and Function of Arteries, Capillaries, and Veins. The walls of arteries and veins have three layers or tunics: 1  An outer layer (tunica adventitia) of connective tissue with collagen fibers. 2  A middle layer (tunica media) of circularly arranged smooth muscle and elastic fibers.
You might have heard that eating chocolate or greasy foods can cause acne, but these are both just myths. The truth is that food has little to do with breakouts. Acne occurs when the openings of hair follicles become blocked with oil secretions, dead skin cells and bacteria.
Youâve probably heard that eating chocolate causes acne. Or that drinking plenty of water will help your skin look healthier, maybe even smooth out a few wrinkles. Or perhaps that loading up on antioxidant-rich foods may undo some of the damage from those years of sun worship. But are any of these beliefs actually true?