Human Nutrition and Digestive System Functions

Essential Nutrients and Digestion

1. Nutrients are natural products or substances produced to provide our cells with what they need to live. They can be of two types: inorganic and organic.

6. Changes food nutrients into simple substances that cells can enter.

The Digestive Tract Components

7. The digestive tract consists of:

• Cavity: Mouth (teeth and tongue), pharynx, and esophagus.
• Stomach: Cardia, stomach, pylorus.
• Intestines: Small and large intestine, colon, appendix, blind, rectum, and anus.
• Glands: Salivary, intestinal, gastric, pancreas, and liver.

8. Produces digestive juices and pours them into the digestive tract.

9. These are compounds containing a variety of substances, including digestive enzymes.

10. Proteins are part of the digestive juices; their function is to accelerate the decomposition of food nutrients.

12. Bile fragments (emulsifies) fat into fat droplets, thereby facilitating the action of digestive juices on fats.

Mechanical and Chemical Digestion

13. This is the process of food transformation as it passes through the digestive tract. It can be:

• Mechanical: Shredding, swallowing, and movements.
• Chemical: Occurring from the mouth to the stomach and intestine.

15. Food processing involves transforming substances into smaller, more soluble nutrients with the help of digestive enzymes. This occurs in three locations:

• In the mouth: Saliva contains the enzyme amylase, which indicates the digestion of carbohydrates.
• In the stomach: The gastric glands secrete gastric juice, which contains hydrochloric acid and the pepsin enzyme, which indicates the digestion of proteins.
• In the intestine (gut): Juices from the intestine, pancreas, and bile are poured in. Pancreatic juice contains the enzyme lipase, which breaks down fats, and other enzymes that decompose carbohydrates and proteins.

Key Digestive Enzymes

16. Digestive enzymes include:

• Amylase: Decomposes complex carbohydrates into simple sugars.
• Pepsin: Decomposes protein chains into smaller amino acids.
• Lipase: Decomposes fats.

Nutrient Absorption

17.

• The small intestine: Absorption of most organic nutrients occurs through the villi.
• The large intestine: Most water and minerals are absorbed here.

18. Factories for synthesizing some proteins.

Functions of Nutrients

20. This provides all types of nutrients in adequate amounts to keep our body in good condition, ensuring smooth development.

21. Functions of Nutrients:

• Plastics (Building): Construct and replenish our body.
• Energetic (Fuel): The energy released is used for movement or maintaining body functions.
• Regulatory: Ensures that bodily processes develop normally.

26. Fundamental component of the cellulose wall of plant cells. It facilitates intestinal transit and is able to absorb a large amount of water.