"Digestion and Absorption" Human Nutrition PPT Courseware 3

Description

"Digestion and Absorption" Human Nutrition PPT Courseware 3

learning target

1. Describe the components of the human digestive system.

2. Based on the digestive system diagram, outline the process of food digestion

3. Through the experiment of exploring the changes of steamed buns in the mouth, we can draw reasonable conclusions about the preliminary changes of food in the digestive system.

Self-study guidance

1. What two parts does the human digestive system consist of, and what structures do they include?

2. What changes occur to food in the mouth?

3. What is digestion and which nutrients are digested first?

4. In what organ are digestive enzymes mainly found? Where do starches, proteins, and fats begin to be digested?

5. In the digestive tract, what is the role of peristalsis in the esophagus, stomach, small intestine, and large intestine?

Explore the changes of steamed buns in the mouth

Ask each student to pick up the steamed buns on the experimental table, chew the steamed buns carefully, and tell them what they taste?

Starch is the main ingredient of steamed buns. Starch has no sweet taste, and the maltose formed after starch is decomposed by salivary amylase has sweet taste.

The concept and whole process of digestion

Based on the research just now, can you summarize the concept of digestion?

Starch, fat, and protein in food are all organic matter with large molecules and complex structures. After entering the digestive system, they are gradually broken down into simple substances before they can be absorbed by the human body. This process is called digestion.

Digestive enzymes

Salivary glands------secret saliva, in which salivary amylase can initially digest starch

Gastric gland ---- secretes gastric juice, the protease in it can preliminarily digest the protease

Intestinal glands---secret intestinal juice, which contains water and enzymes for digesting sugars, proteins and fats

Pancreas - secretes pancreatic juice, which contains enzymes that digest sugars, proteins and fats

digestive tract

Esophagus---can move and push food into the stomach-

Stomach - grinds food through peristalsis to fully mix food with gastric juice and perform preliminary digestion

Small intestine - promotes digestion and absorption of nutrients through peristalsis and pushes food into the large intestine

Large intestine - pushes food and food residues to the anus through peristalsis

When Xiao Ming was eating an apple, he accidentally swallowed the seeds. This apple seed experienced a day's adventure in Xiao Ming's digestive tract. It first encountered a monster with sharp tops and bottoms like a steel rolling mill, which almost crushed it to pieces; just after escaping a disaster, it encountered "acid rain" again; then it got into a long and narrow maze, and it After walking here for a long time, many of the objects around me mysteriously disappeared. After exiting the maze, it almost went into a dead end. Fortunately, it changed direction in time; then it somehow got mixed up with some smelly things; finally. They left Xiao Ming together when Xiao Ming went to the toilet. Please analyze this apple seed

(1) Where did it encounter a monster like a steel rolling mill?

(2) Where does it encounter "acid rain"

(3) What is the long and narrow "maze"? Why do so many substances mysteriously disappear here?

(4) What is the "dead end"?

(5) Where does it get mixed up with something very smelly?

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For more information about the "Human Body's Nutrient Digestion and Absorption" PPT courseware, please click the Human Body's Nutrient Digestion and Absorption ppt tab.

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Update Time: 2024-11-22

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