<span>In humans, a simple columnar epithelium lines most organs of the digestive tract including the stomach, small intestine, and large intestine. Simple columnar epithelia line the uterus.</span>
Positron Emission Tomography scan of the brain of cocaine addicts showed that the drug affects how the brain use glucose. Cocaine users' brain cannot use glucose efficiently and there are also reduced metabolic activity in other areas of the brain.
