The document summarizes the key components and processes of the human digestive system. It describes how the digestive system breaks down the three main macromolecules (carbohydrates, proteins, lipids) through both physical and chemical digestion using mechanical and enzymatic actions. Various organs and glands secrete enzymes and acids that break down nutrients into smaller components as food moves through the alimentary canal, culminating in the absorption of nutrients and elimination of waste.

1. Digestive System

2. Nutrients
• Section 48-1 : Review on own
• Carbohydrates
• Proteins
• Fats •Elements found in the compound
• Lipids •Function of the compound
• Vitamins •Examples of the compound
• Minerals •Monomer of the compound
• Water

3. Overview of Digestive System
Please read but do not take notes on this slide.
• The digestive system consists of the alimentary canal as well as
the organs and glands that contribute digestive enzymes and
other products to specific portions of the canal.
• In processing the food you eat, your digestive system uses
mechanical and chemical methods.
• Three major types of macromolecules must be broken down
during digestion—carbohydrates, proteins, and lipids.
– When these macromolecules are broken down sufficiently—
into individual glucose monomers, amino acids, and fatty
acids, respectively—those components (and water) must be
absorbed into the body at the small intestine.
• Wastes proceed through the large intestine, where the feces
form and more water is absorbed.

4. Types of Digestion
• Physical Digestion
• Chemical Digestion
• Both

5. Physical Digestion
• Mechanical Digestion
• Macromolecule is PHYSICALLY broken
down into SMALLER pieces in order to
increase SURFACE area to maximize
ENZYME action.
• Examples:
– Chewing
– Churning

6. Chemical Digestion
• Digestive enzymes are involved by
CHEMICALLY breaking the bonds on
the macromolecules until MONOMERS
are formed.
• Examples:
– Salivary amylase breaks down starch

8. Route of Digestion
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Anus

9. As food directly passes through the
gastrointestinal tract
or
alimentary canal
specific secretions that aid in digestion
are released along the way.

11. Accessory Organs
• Aids in digestion
• BUT…
• Food does NOT pass into these organs.
• Instead these organs SECRETE fluids that will
enter the alimentary canal through DUCTS.
• Examples:
– Liver – Pancreas
– Gallbladder – Salivary Glands

12. Accessory
Organs

14. Digestive Secretions
• Helps with breaking down of foods
• All are hydrolysis reactions
• Some are enzymatic reactions
• Others are NOT.

15. Salivary amylase
• FUNCTIONS
– Mouth
• MADE
– Salivary glands
• PURPOSE
– Polysaccharide → Disaccharide
– Example
• Starch → Maltose

16. Pepsin
• FUNCTION
– Stomach
• MADE
– Gastric Glands
• PURPOSE
– Protein → Polypeptides

17. Pancreatic amylase
• FUNCTION
– Small intestine
• MADE
– Pancreas
• PURPOSE
– Polysaccharide → Disaccharide

18. Pancreatic lipase
• FUNCTION
– Small Intestine
• MADE
– Pancreas
• PURPOSE
– Lipids → 3 Fatty Acids + Glycerol

19. Trypsin/Chymotrypsin
• FUNCTION
– Small intestine
• MADE
– Pancreas
• PURPOSE
– Polypeptides → Peptides

20. Intestinal lipase
• FUNCTION
– Small Intestine
• MADE
– Intestinal glands
• PURPOSE
– Lipids → 3 Fatty Acids + Glycerol

21. Intestinal peptidase
• FUNCTION
– Small Intestine
• MADE
– Intestinal glands
• PURPOSE
– Peptides → Amino Acids

22. Maltase/Sucrase/Lactase
• FUNCTION
– Small Intestine
• MADE
– Intestinal glands
• PURPOSE
– Disaccharides → Monosaccharides

23. Additional Secretions for
Digestion

24. Saliva
• FUNCTION
– Mouth
• MADE
– Salivary Glands
• PURPOSE
– Begins digestion of food

25. Mucus
• FUNCTION • FUNCTION
– Mouth – Stomach
• MADE • MADE
– Salivary glands – Gastric pits
• PURPOSE • PURPOSE
– Lubricates food – Protects lining from
HCl

26. Gastrin
• FUNCTION
– Stomach
• MADE
– Gastric pits
• PURPOSE
– Hormone that stimulates HCl production

27. Gastric fluid/HCl acid
• FUNCTION
– Stomach
• MADE
– Gastric pits
• PURPOSE
– Converts pepsinogen → pepsin
– Kills bacteria

28. Secretin
• FUNCTION
– Small intestine
• MADE
– Intestinal glands
• PURPOSE
– Hormone that stimulates the liver and
pancreas to secrete fluid

29. Bile
• FUNCTION
– Small Intestine
• MADE
– Liver
• PURPOSE
– Emulsifies fats/lipids

30. Sodium bicarbonate
NaHCO3
• FUNCTION
– Small intestine
• MADE
– Pancreas
• PURPOSE
– Neutralizes stomach acid

31. Carbohydrates
Organ Before Enzyme After
Mouth Starch Salivary amylase Disaccharides
Starch Pancreatic amylase Disaccharides
Maltose Maltase
Small
intestine Sucrase Mono-
Sucrose saccharides
Lactose Lactase

32. Digestion of Carbohydrates
Click on the link above and view
the animation associated with
Digestion of Carbohydrates

33. Proteins
Organ Before Enzyme After
Stomach Protein Pepsin Polypeptides
Trypsin
Polypeptides Chymotrypsin Peptides
Small
intestine
Peptides Peptidase Amino acids

34. Digestion of Proteins
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the animation associated with
Digestion of Proteins

35. Lipids
Organ Before Enzyme After
Small Emulsified Pancreatic lipase 3 Fatty acids +
Intestine Lipids Intestinal lipase Glycerol

36. Digestion of Lipids
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the animation associated with
Digestion of Lipids

37. Review the
Structures
of the
Digestive System
Click on this phrase for Review Information