Food Digestion

So what happens to that Quarter Pounder with Cheese, Large Fries

and Chocolate Milk Shake

Understanding Digestive Enzymes

Digestion is the breakdown and absorption of food

ABSORPTION ONLY TAKES PLACE IN THE SMALL INTESTINE

Classified by their Substrates

• Protease & Peptidase• Lipases• Carbohydrase

• Break proteins into amino acids• Split fat into 3 fatty acids• Split carbs into smaller sugars - Glucose

Digestion occurs at the

• Oral Cavity

• Stomach• Duodenum• Jejunum

TeethPeristalsisVilliVilli

Tongue Acids Enzymes Enzymes

Saliva Enzymes Neutralizers

Digestive Enzymes are produced

• Salivary Glands• Stomach• Pancreas• Small Intestine

Teeth

Mechanical• Mastication

End Product• Ground Food

Chemical• None

Affects• None

Tongue

Mechanical• Moves food back

and forth

End Product• Bolus

Chemical• None

Affects• None

Hard Palate

Mechanical• Helps to shape

bolus

End Product• Round Bolus

Chemical• None

Affects• None

Salivary Glands

Mechanical• Moistens

End Product• Moist Bolus

Chemical• Amylase

Affects• Polysaccharides

– Starches

Pharynx

Mechanical End Product

Chemical Affects

No Mechanical or Chemical change to Food. Pushes Food Via Peristalsis

Esophagus

Mechanical End Product

Chemical Affects

No Mechanical or Chemical change to Food. Pushes Food Via Peristalsis

StomachMechanical• Churns via

Peristalsis• Three Muscles

End Product• Chyme

Chemical• Pepsin• Gelatinase• Gastric Amylase• Gastric Lipase• Rennin• HCl• Gastrin

Affects• Protein• Breaks down Muscle Collagen• Breaks down Butter Fats• Milk Fats• Milk Proteins• Activates Enzymes/Breaksup Lg Food

• Stimulates more HCl Production

Liver

Mechanical• None

End Product• Still Chyme

Chemical• Bile

Affects• Emmulsifies Fat

Gall Bladder

Mechanical• None• Bile does the

Breakdown

End Product• Still Chyme

Chemical

Stores Bile

CCK

Affects• Released with Lg Fat quantities• Stimulates Gall Bladder to Void

NOTE: Bile Released INTO the Duodenum!

PancreasMechanical• None

End Product• Chyme

Chemical• Bicarbonates• Trypsin• Chymotrypsin• Pancreatic Amylase• Steapsin• Insulin• Secretin

Affects

Neutralizes Stomach Acids

Proteins

Proteins

Polysaccharides

Fats

Regulates Blood Glucose

Stimulates NaCO2 Production

NOTE: Pancreatic Juices Released INTO the Duodenum!

Small Intestine

Mechanical• Pushes Chyme

Along• Peristalsis• Water Absorption

End Product• Chyme• NutrientAbsorption

Chemical• Pepidase• Lactase• Sucrase• Amylase

Affects• Proteins• Milk Fats• Sugars• Polysaccharides

NOTE: SI Enzymes found in Jejunum!

Large Intestine

Mechanical• Absorbs Water• Absorbs Salts

End Product• Feces

Chemical Affects

• Bacterial Action to Break down some Cellulose• Bacterial Action to regulate fluidity of Feces• Water Absorption Regulation: Diarrhea vs Constipation

Gastric Juices

Production• All the enzymes

are produces by the Stomach

End Product• Pepsin• HCl

Actions• HCl Converts Pepsinogen into Pepsin• Pepsinogen is stimulated by Gastrin• Gastrin is stimulated by Smell, Sight, Taste Thinking

Pancreatic Juices

Production• All the enzymes

are produces by the Pancreas

Actions• Secretin important to stimulate NaCO2 production to

neutralize the Strong Stomach Acids• Prevents burning away of Duodenum