ANIMAL PHYSIOLOGY
DIGESTION IN HUMANS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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7
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2
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8-9
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4
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Detailed explanation-1: -The pH of the digestive juices within the human small intestine is between 7.5 and 8.5.
Detailed explanation-2: -The pH gradually increases in the small intestine from pH 6 to about pH 7.4 in the terminal ileum. The pH drops to 5.7 in the caecum, but again gradually increases, reaching pH 6.7 in the rectum. The physiological background of these pH values is discussed.
Detailed explanation-3: -In the small intestine, the enzymes that “work” there need an alkaline pH in order to have optimum working conditions. A second reason is that strong acids (like hydrochloric) can end up damaging the lining of your intestine.
Detailed explanation-4: -After swallowing, the food reaches the stomach where upper and lower parts of stomach have different pH values. The upper part has a pH of 4−6.5, while the lower part is highly acidic with a pH of 1.5−4.0. It then enters the intestine which is slightly alkaline, with a pH of 7−8.5.
Detailed explanation-5: -The pancreas secretes the bicarbonate ions through bile juice in the small intestines. These bicarbonates neutralize the acidic pH of the food from stomach and create an alkaline pH, thus maintain the required pH in small intestines.