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.
Drinking Gallons of Water Wonât Hydrate Your Skin. At All. The amount of water you drink plays zero role in your skinâs appearance, says Amy Wechsler, MD, and YouBeauty Dermatology Advisor. Although it sounds like an easy fix, it wonât help combat dry skin or clear up your acne. Bummer! The liquid water you consume passes through you (via urine) and has no effect on outward body surfaces.