Digestion
How it works
How do we get nutrients?
•Nutrients come from foods that we eat and digest.
Food is processed in the body in 3 phases:
• Ingestion
• Digestion
• Egestion
What is Ingestion?
The process of taking food into the body (eating).
• Occurs in the mouth
• During ingestion, mechanical and chemical digestion takes place in the mouth .
• Once food is swallowed, ingestion ends and digestion begins.
Ingestion:
Digestion
• Digestion breaks foods down chemically to access the nutrients the body needs.
• During digestion, larger pieces of food are broken down into smaller pieces mechanically and chemically.
• Complex chemicals in food are changed into simpler ones.
Digestion
• Begins in the esophagus and continues through the small intestine.
• Most digestion takes place in the stomach and small intestine.
• Nutrients are absorbed at the end of digestion.
Digestion: the process of breaking down food by mechanical and chemical action.
Egestion
• Egestion: removal of undigested food from the digestive tract.
•Water is absorbed from the undigested mass.
•Egestion occurs in the large intestine, rectum, and anus.
•Egestion only describes the removal of solid wastes.
Egestion
Label Your Diagram
Color the organs of the digestive system in based on which processes they are involved:
Ingestion = REDDigestion = BLUEEgestion= GREEN
How is food digested?
There are two types of digestion:
•Mechanical Digestion
•Chemical Digestion
Mechanical Digestion
MechanicalDigestion:
The breaking down of large food molecules by the movement of your teeth and tongue.
•Chewing food, and peristalsis is mechanical digestion.
•Food is crushed, cut, and mushed up to increase surface area.
•The surface area increases to aid with chemical digestion.
What are enzymes andwhat do they do?
•Chemical digestion can only take place with
enzymes and digestive juices.
•Enzyme: a substance that acts as a catalyst
to speed up the digestive process.
Enzymes are secreted by the
digestive organs to breakdown
food molecules
Enzymes of the Digestive System
•Amylase- salivary enzyme, begins the breakdown of carbohydrates.•Lipase- pancreatic enzyme, breaks down lipids.•Sucrase- small intestine enzyme, breaks down carbohydrates.•Pepsin- stomach enzyme, breaks down proteins.
Chemical Digestion
ChemicalDigestion:
The chemical breakdown of food into smaller molecules.
•Carbohydrates
•Proteins
•Fats
•Amino acids
•Fatty acids
•Monosaccharides and polysaccharides
Chemical Digestion
•Food is broken down to very small molecules and nutrients to be absorbed.
•The nutrient molecules are absorbed in the small intestine and carried by your bloodstream to diffuse into your cells.
Digestion episode
Digestion
http://kidshealth.org/kid/htbw/_bfs_DSmoviesource.html
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