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.
The same study linking milk consumption to acne showed that those drinking skimmed milk had a 44 per cent increase in the likelihood of developing spots. It is thought that processing the milk increases the levels of hormones in the drink - which in turn affects acne sufferers. 8. Milk could give you a cough.