Digestive System

Nutrients

• Section 48-1 : Review on own• Carbohydrates• Proteins• Fats• Lipids• Vitamins• Minerals• Water

•Elements found in the compound•Function of the compound•Examples of the compound•Monomer of the compound

Overview of Digestive SystemPlease 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.

Types of Digestion

• Physical Digestion

• Chemical Digestion

• Both

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

Chemical Digestion

• Digestive enzymes are involved by CHEMICALLY breaking the bonds on the macromolecules until MONOMERS are formed.

• Examples:– Salivary amylase breaks down starch

Route of Digestion

• Mouth

• Pharynx

• Esophagus

• Stomach

• Small intestine

• Large intestine

• Anus

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

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– Gallbladder

– Pancreas– Salivary Glands

Accessory Organs

Digestive Secretions

• Helps with breaking down of foods

• All are hydrolysis reactions

• Some are enzymatic reactions

• Others are NOT.

Salivary amylase

• FUNCTIONS– Mouth

• MADE – Salivary glands

• PURPOSE – Polysaccharide Disaccharide– Example

• Starch Maltose

Pepsin

• FUNCTION– Stomach

• MADE– Gastric Glands

• PURPOSE– Protein Polypeptides

Pancreatic amylase

• FUNCTION– Small intestine

• MADE– Pancreas

• PURPOSE– Polysaccharide Disaccharide

Pancreatic lipase

• FUNCTION– Small Intestine

• MADE– Pancreas

• PURPOSE– Lipids 3 Fatty Acids + Glycerol

Trypsin/Chymotrypsin

• FUNCTION– Small intestine

• MADE– Pancreas

• PURPOSE– Polypeptides Peptides

Intestinal lipase

• FUNCTION– Small Intestine

• MADE– Intestinal glands

• PURPOSE– Lipids 3 Fatty Acids + Glycerol

Intestinal peptidase

• FUNCTION– Small Intestine

• MADE– Intestinal glands

• PURPOSE– Peptides Amino Acids

Maltase/Sucrase/Lactase

• FUNCTION– Small Intestine

• MADE– Intestinal glands

• PURPOSE– Disaccharides Monosaccharides

Additional Secretions for Digestion

Saliva

• FUNCTION– Mouth

• MADE– Salivary Glands

• PURPOSE– Begins digestion of food

Mucus

• FUNCTION– Mouth

• MADE– Salivary glands

• PURPOSE– Lubricates food

• FUNCTION– Stomach

• MADE– Gastric pits

• PURPOSE– Protects lining from

HCl

Gastrin

• FUNCTION– Stomach

• MADE– Gastric pits

• PURPOSE– Hormone that stimulates HCl production

Gastric fluid/HCl acid

• FUNCTION– Stomach

• MADE– Gastric pits

• PURPOSE– Converts pepsinogen pepsin– Kills bacteria

Secretin

• FUNCTION– Small intestine

• MADE– Intestinal glands

• PURPOSE– Hormone that stimulates the liver and

pancreas to secrete fluid

Bile

• FUNCTION– Small Intestine

• MADE– Liver

• PURPOSE– Emulsifies fats/lipids

Sodium bicarbonate

• FUNCTION– Small intestine

• MADE– Pancreas

• PURPOSE– Neutralizes stomach acid

NaHCO3

Carbohydrates

Organ Before Enzyme After

Starch Disaccharides

Small intestine

Starch

Maltose

Sucrose

Lactose

Mouth Salivary amylase

Pancreatic amylase Disaccharides

Maltase

Sucrase

Lactase

Mono-saccharides

Digestion of Carbohydrates

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Proteins

Organ Before Enzyme After

Polypeptides

Small intestine

Polypeptides

Stomach Protein Pepsin

TrypsinChymotrypsin Peptides

Peptides Peptidase Amino acids

Digestion of Proteins

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Digestion of Proteins

Lipids

Organ Before Enzyme After

3 Fatty acids + Glycerol

SmallIntestine

Emulsified Lipids

Pancreatic lipaseIntestinal lipase

Digestion of Lipids

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Digestion of Lipids

Review the Structures

of the Digestive System

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