Chapter 2 of the second semester of the first year of junior high school biology digestive system pr

I have summarized the following points:

1. There are five types of digestive glands: salivary glands, gastric glands, intestinal glands, pancreas, and liver.

2. Salivary glands: secrete saliva, which contains salivary amylase.

Gastric glands: secrete gastric juice containing hydrochloric acid and proteases.

Intestinal glands: secrete intestinal fluid, which contains enzymes that digest sugars, proteins, and fats.

Pancreas: secretes pancreatic juice and contains enzymes that digest sugars, proteins, and fats.

Liver: secretes bile (bile itself does not have enzymes to digest food, but bile has an emulsifying effect and can promote the digestion of fats).

Among them: the digestive glands in the digestive tract are stomach glands and intestinal glands.

The digestive glands outside the digestive tract are salivary glands, pancreas, liver.

Saliva secreted by the salivary glands is injected into the mouth.

Both pancreatic juice secreted by the pancreas and bile secreted by the liver are injected into the small intestine (because the 12 denum is the starting part of the small intestine).

3. Amylase digests starch, protease digests protein, and in the same way, what enzyme it contains has the effect of digesting what. As a result, starch is digested from the mouth (due to salivary sweat salivary amylase); Protein is digested from the stomach (because the stomach begins to have proteases); Fats are digested from the small intestine (because of the presence of lipases in intestinal and pancreatic juices in the small intestine).

4. The small intestine is the main absorption organ, and it is also the organ that contains the most digestive juice, the small intestine not only contains the intestinal fluid secreted by the intestinal glands, but also the pancreas and liver outside the digestive tract secreted and injected into the pancreatic juice and bile.

5. The structures related to the absorption function of the small intestine are: there are folds in the small intestine, and there are villi on the folds, and the villi contain abundant capillaries. The folds and villi of the small intestine greatly increase the absorption area of the small intestine.

6. Starch is decomposed into maltose by salivary amylase in the oral cavity is only preliminarily digested, sugars (such as starch, etc.) are digested in the digestive tract, and finally decomposed into glucose and directly absorbed by the human body, and protein is finally decomposed into amino acids and directly absorbed by the human body. In other words, no matter what kind of sugars and proteins they are, what can be directly absorbed by the body are the decomposed glucose and amino acids.

Dizzy! Try it yourself! Don't always rely on other people, I'm all biological, and don't always ask other people. Use your own brain.

Creatures should read more books;

If you want to get a high score, you have to memorize the teacher's handouts.

Each place focuses on a different story.

It's better to borrow your classmates' notes to read it.

The starch in food is digested and broken down by saliva in the mouth, and after the starch is broken down, it becomes maltose, which is broken down and absorbed by intestinal fluid in the small intestine and will be broken down into glucose. 、

Protein is broken down in the stomach by gastric acid, and the protein is broken down into polypeptides, which in turn are broken down into amino acids in the intestinal fluid of the small intestine.

There is also fat in the small intestine that is broken down by bile into fat particles, which are then broken down into glycerol and fatty acids by intestinal fluid.

Then the small intestine pushes the food debris into the large intestine through peristalsis, and after that... Hee-hee......It becomes poop.

Repentance]:Basic training to break through1. Pharynx.

Stomach. Small intestine.

2、c 3、a

4, a5, a, b- -b b, c- -c b- -a6, (1) small intestine and stomach.

2) Stomach and small intestine.

Strengthen capacity improvement1、b 2、c

3、c 4、d

5. Small intestine. 6. (1) Stomach.

2）b、c、d

3) Intestinal juice, pancreatic juice, bile.

4) A7, (1) starch, protein, fat.

2) Small intestine. 3) Oral saliva, starch, maltose, stomach protein.

4) Glycerol and fatty acids.

Extension of classroom knowledgeDisagree. In patients with liver disease, the secretion of bile is insufficient, which affects the digestion of fat, and the main ingredient of braised pork is fat.

Links to exam questions1、a 2、c

3、c 4、b

5. (1) Sleeping liquid.

2) Turn blue without stirring.

and 3) the effect of temperature on the digestion of starch by saliva.

4) The steamed bread crumbs are not fully mixed with saliva (or shouting points before stirring and not filling the skin, the test tube is not kept warm enough, and the saliva starch in the saliva.)

The amount of enzyme is not enough, and the answer to the case of Ranye is reasonable) recommended:

Oral cavity: saliva, salivary amylase, digestive starch non-absorption substances stomach: gastric juice, pepsin, digestive proteins, absorption of water, alcohol pancreas: pancreatic juice, trypsin, pancreatic amylase, pancreatic maltase, pancreatic lipase, digestive proteins, starch, fat, maltose non-absorbing substances.

Liver: bile, does not contain enzymes, plays the role of emulsifying fats, does not absorb substances small intestine: intestinal fluid, protease, amylase, maltase, lipase, intestinal peptidase, digests protein, starch, fat, maltose, polypeptides, absorbs amino acids, glucose, water, inorganic salts, glycerol, fatty acids, vitamins, etc.

Large intestine: does not contain enzymes, does not digest, absorbs only water, inorganic salts.

Mouth: saliva Stomach: gastric juice Pancreas: pancreatic juice Liver: bile Small intestine: intestinal fluid Large intestine:

(1) c, because the digestive system passes through the mouth, the esophagus is the stomach.

2) The digestion curve of starch, only starch can be broken down in the mouth and esophagus.

3) d (small intestine).

(1)c

2) Starch, because the curve x falls in the mouth (don't fill in the brackets, the drop actually means digestion), indicating that it is starch.

3）d

C Starch Starch is broken down into maltose D by saliva in the mouth

I choose CAnalysis: The main ingredient of fresh beef is protein, the protease that digests protein is present in gastric juice and pancreatic juice, and the protein is digested into polypeptides, which need peptidase to continue digestion, and peptidase is present in intestinal fluid.

The pH in the stomach is about and below, which is also the most suitable pH for pepsin, and the intestinal fluid and pancreatic juice are both in the small intestine, and the pH value is about 8. If gastric juice is mixed with intestinal or pancreatic juice as in option A or B, the pH will change and both enzymes will lose their effect.

Starch. At.

Oral cavity. Medium quilt.

Ptyalin.

Initial digestion into maltose in.

Small intestine. Medium matching.

Intestinal fluids. Pancreatic juice attack.

Broken down into. Glucose.

Protein. In the stomach is covered.

Pepsin. Preliminary digestion into

Peptides. It is broken down into pancreatic juice and intestinal fluid in the small intestine. Amino acid.

Fat. In the small intestine is covered.

Bile. Initial digestion into fat.

Particles. In the small intestine, it is decomposed by intestinal fluid and pancreatic juice.

Glycerol. Fatty acid.

Starches, proteins, and fats are thoroughly digested in the small intestine.

1.The stomach is located on the right side of the human body below the rib cage. Its main function is chemical digestion, which allows food and gastric juices to be well mixed and physically digested

2.Food is digested in the digestive tract and eventually broken down into nutrients such as grape sugar and amino acids that can be absorbed by the body.

3.The digestive juices that can digest proteins, sugars, and fats are intestinal juice and pancreatic juice 4In the hollow bend human body, the organs that break down proteins into amino acids are the stomach and small intestine 5

The nutrients that can be absorbed by the capillary lymphatic vessels of the villi of the small intestine are fatty acids and glycerol 6The nutrients absorbed by the human body enter the blood circulation through the digestive wall Judgment:1

The various organs within the digestive tract have the function of digestion and absorption. (False.)

2.The liver secretes bile, which promotes fat breakdown and absorption. (False.)

3.The sweet taste of chewing the steamed bun is due to the fact that the starch is broken down into glucose by the action of enzymes. (False.)

1. The y-curve is the digestion process of fat, because the initial and final digestion sites of fat are in the small intestine.

2. The initial digestion site of starch is in the oral cavity, the initial digestion site of fat is in the small intestine, and the initial digestion site of protein is in the stomach.

3. D is the small intestine, with intestinal glands, which can secrete intestinal fluid, and contain enzymes for digesting starch, Qingxin fat and protein. The liver and pancreas secrete bile and pancreas that also return to the small intestine. Bile contains no digestive enzymes and can only emulsify fats.

Pancreatic juice contains enzymes that digest starch, fat, and protein. If you only ask about digestive enzymes, proteolytic enzymes, lipases, and amylases will do.

;2.starch in the A mouth, fat in the D small intestine, protein in the C stomach; 3.Proteolytic enzymes, lipases, amylases.