Reported December 2008

How Does Digestion Work?: When we consume food, it is not usually in a form that the body can use as nourishment. First, it must be converted into smaller molecules of nutrients, which can be absorbed into the blood and carried to cells throughout the body, providing the necessary fuel to function. This is the job of the digestive system, which is a series of organs joined by a long, twisting tube that runs from the mouth to the anus. Food enters the esophagus through the mouth. The esophagus connects the throat and the stomach. There is a ring-like valve where the esophagus meets the stomach, which relaxes to allow food to pass into the stomach before closing up again. The stomach stores the food and liquid, and then mixes it all up with digestive juices. The walls of the stomach and the digestive system's other major organs contain muscles, which enable them to move, propelling food and liquid through the digestive tract by squeezing itself like a wave. This is called peristalsis.

Once the stomach has emptied its contents into the small intestine, the partially digested food is dissolved even further by juices produced by the pancreas, liver and intestine. Then it is mixed and pushed along even further as nutrients are absorbed through the intestinal walls into the bloodstream. Waste products include undigested parts of food, like fiber, as well as older cells that have been shed from the intestinal walls. These are passed into the colon before being excreted by the body.

What are Lasers?: "Laser" stands for Light Amplification by Stimulated Emission of Radiation. It describes any device that creates and amplifies a narrow, focused beam of light that contains photons all traveling in the same direction, rather than emitting every direction at once. An opposite example would be a flashlight, where the atoms release their photons randomly in all directions. Laser light contains only one specific color, or wavelength. The type used in this confocal laser endomicroscope produces blue light.

The Optical Society of America contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Eric Vohr
Media Relations and Public Affairs
Johns Hopkins Medicine
Baltimore, MD 21231
(410) 955-8665
evohr1@jhmi.edu

Optical Society of America
Washington, DC 20036-1023
(202) 223-8130
http://www.osa.org
info@osa.org