All blood vessels are specifically structured to perform their function. For example, a capillary is microscopically thin to allow gases to exchange, the arteries are tough and flexible to cope ...

There is no net movement of water in any direction as the concentration is equal on both sides so the level of water in the capillary tube remains the same.

Some birthmarks can cause a problem later on. Treatment can prevent that. Your dermatologist may recommend treatment if your child has a: Strawberry hemangioma on the face or groin: This birthmark ...