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.
Best Foods For Acne: 10 Foods That Prevent Pimples And Irritated Skin. Posted: 11/09/2012 2:29 pm EST Updated: 10/24/2016 2:30 pm EDT. ADVERTISEMENT. If you've always believed chocolate and oily foods cause acne, it's finally time to put that myth to rest. It's one of the biggest misconceptions about acne, but the only thing these foods can actually do is raise cholesterol levels, says Rachelle Wood, registered holistic nutritionist in Charlottetown P.E.I.