Question

The pH of succus entericus is
A. 6.6
B. 5.6
C. 2.0
D. 7.8

Answer 1

Hint: Succus entericus is the juice present in the small intestine, thus also known as intestinal juice. It has a variety of enzymes such as disaccharidases, lipases, dipeptidases, nucleosidases, etc., which are used in the digestion of food.

Complete answer:
The mucosal epithelium layer of the intestine contains goblet cells that secrete mucus which helps in the lubrication. Intestine also has a brush border like a layer of villi. The secretion of these two layers i.e. secretion from the brush border cells of mucosa and secretion from the goblet cells, together produce the intestinal juice, succus entericus. Succus entericus is watery yellowish liquid secreted from the glands present on the walls of the small intestine.
The mucus and bicarbonates present in the succus entericus protects the intestine layers from acids of the stomach and also provides an alkaline medium for the enzymes to break down the food particles. The pH in the stomach is highly acidic (1.8) and increases in the small intestine up to 7.8.

Thus the correct option is (D) 7.8.

Additional Information: The role of succus entericus is to activate the enzyme trypsinogen into its active form, trypsin. This enzyme is activated by another enzyme enterokinase which is present in the succus entericus. Intestinal juice also helps in digestion as many enzymes are present in it. It also contains hormones and mucus.

Note: The mucosa (innermost) layer of the intestine forms a villi known as microvilli which increases the surface area for better absorption of food. These villi form crypts between the bases of the villi which are known as crypts of Lieberkuhn.