1 In 1990, Barack Obama was elected as the first black president of the Harvard Law Review. 2  Obama, who graduated from HLS in 1991, would later represent Illinois in the U.S Senate, and in 2008 would become the 44 th President of the United States, and the first African-American president.
Most cancers in the lung are carcinomas-cancers of epithelial cells. The top pair of images shows the normal epithelium of the bronchi. This photomicrograph is greatly enlarged. The next three pairs of images show three successive stages of abnormal changes in the bronchial epithelium commonly found in smokers.
The epithelium is either columnar or cuboidal. The final branches of the bronchioles are called terminal bronchioles. These have a layer smooth muscle surrounding their lumens. Stimulation of the vagus nerve (parasympathetic) causes the smooth muscle to contract, and reduce the diameter of the terminal bronchioles.he trachea branches to give rise to two primary (main) bronchii. These then branch successively to give rise in turn to secondary and tertiary bronchii. These then branch to give rise to several orders of progressively smaller airways called bronchioles, the smallest of which are called terminal bronchioles.