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In the Stomach Hi, If you recall, last week we left off at the point where food was beginning it's journey to the stomach. Let's follow it on its journey shall we? After the food rolls off the tongue it is no longer under voluntary control. It is now moved through the system under the control of the involuntary nervous system. After leaving the tongue, it will take about 8 seconds for the swallowed food to reach the stomach travelling down the oesophagus. The food passes down this tube in a wave-like motion. These peristaltic waves are so strong that even if suspended upside down, a person can swallow small quantities of food which will work it's way, against gravity, to the stomach. This is why astronauts can swallow in zero-gravity Pure liquid can move down the oesophagus in only 1 second, 8 times faster than the peristaltic waves move the solid food. The food then passes into the stomach through an opening called the cardiac orifice. As soon as food enters the stomach, a hormone called gastrin is released into the bloodstream. This hormone is carried to the gastric glands in the stomach, which causes them to secrete digestive juices, which contain primarily hydrochloric acid & digestive enzymes. The hydrochloric acid makes the stomach a very acid environment with a PH factor between 1.5 and 3.0 (as compared with lemon juice with a factor of 2) This high acidity serves two functions 1) it acts as a denaturant in digestion of proteins and 2) it kills small parasites that are often found in all foods. 3 primary enzymes are also present in the gastric juices. 1) Pepsin, which aids in the hydrolysis of proteins. 2) lipase, which aids in the hydrolysis of fats and 3) rennin, found only in the gastric juices of infants. Its primary function is the hydrolysis of milk proteins. Adults do not have the rennin enzyme in sufficient quantity to digest milk products. Consequently, the only time milk should be used in the diet is during infancy. The stomach empties at the slow rate of up to 5 hours per 1 kg of food, depending on the type of food. Water & liquids leave the stomach most rapidly, carbohydrates empty more quickly than proteins, proteins in turn more quickly than fat. Within 5 minutes after fat enters the stomach, a hormone called enterogastrone enters the blood stream and travels to the stomach. This hormone inhibits the motion of the stomach and causes it to empty at a much slower rate. Next week we will continue the journey to the intestine & colon. Wishing you a wonderful week, he Crazy Nut Team