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.
âSugar can absolutely cause breakouts, because itâs pro-inflammatory,â Lipman confirms. âAcne is considered an inflammatory condition, and someone with acne-prone skin should follow an anti-inflammatory diet.â. That doesnât mean you have to give up sweetness for good, though.