The Digestive Process Begins

1
The Digestive Process Begins

• Key Concepts
• 1. What functions are carried out in the
  digestive system?
• 2. What roles do the mouth, esophagus, and
  stomach play in digestion?

2
Key Terms

• Esophagus
• Mucus
• Peristalsis
• Stomach

• Digestion
• Absorption
• Saliva
• Enzyme
• Epiglottis

3
The Digestive Systemhas three main functions.

• 1. Breaks down food into molecules the body can
  use
• 2. Molecules are absorbed into blood and carried
  throughout the body
• 3. Wastes are eliminated from the body

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Digestion

• Definition
• Process where your body breaks down food into
  small nutrient molecules
• Two types of Digestion
• Mechanical - Foods are physically broken down
  into smaller pieces bite and chew
• Chemical chemicals produced by body break food
  into smaller chemical building blocks. Ex. Starch
  changed into sugars

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Absorption and Elimination

• Absorption ( keeping the good stuff)
• the process by which nutrient molecules pass
  through the wall of your digestive system into
  your blood.
• Elimination (Getting rid of the bad stuff)
• materials that are not absorbed, such as fiber
  are eliminated from the body as wastes

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Mouth Teeth

• Teeth
• Incisors
• Canines
• Premolars
• molars

• Shred grind and crush food
• Cut food
• Tear and slash
• Crush and grind

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Tongue

• Helps mix food with saliva and assists with
  swallowing
• Sensory organ tastes food

8
Mouth Salivary Glands

• Produce Saliva Contains enzymes that break down
  certain foods into simpler chemicals
• Ex. Starch is broken down into sugars

Enzymes have a specific shape that enables it to
take part in only one kind of reactions
9
The Esophagus

• Function
• Muscular tube from mouth to stomach. Lined with
  mucus. Smooth muscle moves food by peristalsis

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Epiglottis

• Flap that closes over windpipe so no food goes to
  lungs

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The Stomach

• Structure
• Stomach

• Function
• Chemical digestion
• Releases gastric juice pepsin and hydrochloric
  acid
• Stomach lined with mucus to protect it from the
  acid
• Mechanical Digestion
• Contractions of 3 layers of smooth muscle churns
  food