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**Mouth (Oral Cavity)**  
- Ingestion: Food enters the mouth.  
- Mechanical Digestion: Chewing (teeth break down food).  
- Chemical Digestion: Salivary amylase begins breaking down starches into maltose.  
- Bolus Formation: Food is moistened with saliva and shaped into a bolus.  
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**Pharynx (Throat)**  
- Swallowing: Bolus moves from the mouth to the pharynx.  
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**Esophagus**  
- Peristalsis: Wave-like muscle contractions move the bolus down the esophagus to the stomach.  
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**Stomach**  
- Mechanical Digestion: Churning mixes food with gastric juices to form chyme.  
- Chemical Digestion:  
  - Gastric juice (contains hydrochloric acid and pepsin) breaks down proteins into peptides.  
  - Limited digestion of lipids by gastric lipase.  
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**Small Intestine (Duodenum, Jejunum, Ileum)**  
- Duodenum:  
  - Chyme is mixed with:  
    - Bile (from the liver and gallbladder): Emulsifies fats.  
    - Pancreatic enzymes (from the pancreas):  
      - Amylase: Breaks down starch into maltose.  
      - Lipase: Breaks down fats into glycerol and fatty acids.  
      - Proteases (like trypsin): Break down proteins into amino acids.  
  - Neutralization: Bicarbonate (from the pancreas) neutralizes stomach acid.  
- Jejunum & Ileum:  
  - Absorption of nutrients through villi and microvilli:  
    - Carbohydrates → Simple sugars (glucose).  
    - Proteins → Amino acids.  
    - Fats → Fatty acids and glycerol.  
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**Large Intestine (Colon)**  
- Absorption:  
  - Water and electrolytes are absorbed.  
  - Bacteria ferment undigested carbohydrates, producing gases and short-chain fatty acids.  
- Formation of Feces: Undigested material and waste products form feces.  
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**Rectum**  
- Storage of feces until elimination.  
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**Anus**  
- Defecation: Feces are expelled from the body.  
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