What is a joke without digestive enzymes?

(1) The liver is a huge digestive gland, which can secrete bile. Bile does not contain digestive enzymes, but it can emulsify fat and emulsify larger fat particles into smaller ones, which is beneficial to the digestion of fat.

(2) The pancreas consists of endocrine part and exocrine part. The endocrine part is islet, which can secrete insulin and regulate the absorption, utilization and transformation of sugar in the body, such as promoting the synthesis of glycogen from blood sugar and accelerating the decomposition of blood sugar. Therefore, after eating a lot of sugar, the blood sugar concentration will temporarily increase, but under the action of insulin secreted by islets, the blood sugar concentration will gradually return to normal.

(3) The final products of fat are glycerol and fatty acids. (3) Gallbladder is the place where bile is stored. Bile does not contain digestive enzymes, but it can emulsify fat, emulsifying larger fat particles into smaller fat particles, which is beneficial to the digestion of fat, so there are few glycerol and fatty acids here. (5) Small intestine is the main place for digestion and absorption, with a large area; The longest in the digestive tract, about 5-6 meters long; There are many small intestinal villi on the inner surface of small intestine; Intestinal glands secrete intestinal juice. The small intestine contains pancreatic juice, bile and other digestive juices. The villus wall and capillary wall of small intestine are only composed of a layer of epithelial cells, which is beneficial to the absorption of nutrients. ⑥ There are no digestive enzymes in the large intestine, and most of the final digestive products of fat, starch and protein are absorbed in the small intestine, so glycerol and fatty acids, the final digestive products of fat, are rare in the large intestine.

(4) There are various digestive juices in the small intestine, which can digest starch into glucose, protein into amino acids and fat into glycerol and fatty acids. Therefore, there are nutrients in the small intestine: besides water, inorganic salts, vitamins and other substances that do not need to be digested, there are also sugars, protein, fat digestion end products and preliminarily digested substances; Therefore, the digestive tract containing glucose, maltose, starch, amino acids, fat, vitamins and other substances is B small intestine.

So the answer is:

( 1)⑦; liver

(2)④; Islet; insulin

(3)③; ⑥

(4)B