digestive system

• Digestive System

  Body system responsible for the ingestion, digestion, absorption and excretion of waste material that are not needed by the body
• Functions of the Digestive System

  • Mechanical Digestion
  • Chemical Digestion
• Mechanical Digestion


  Muscular movement of the digestive tract physically break down food into smaller particles
• Chemical Digestion


  Aided by enzymes in breaking down food particles into nutrient molecules
• Biomolecules


  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic Acids
• Carbohydrates


  Monosaccharides (simple sugars) that are a source of energy
• Lipids


  Fatty acids that are a source of energy and heat
• Proteins


  Amino acids that are used for muscle building and protection from foreign organisms
• Nucleic Acids


  Nitrogenous bases with phosphate groups and sugars that are used for the synthesis of the blueprint of life (DNA)
• Two Major Parts of the Digestive System

  • Digestive Tract (Alimentary Canal)
  • Accessory Organs
• Parts of the Digestive Tract

  • Mouth (Oral Cavity)
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine
• Accessory Organs


  • Tongue
  • Salivary Glands
  • Liver
  • Gall Bladder
  • Pancreas
• Oral Cavity (Mouth)


  Where mastication (cutting, tearing, and crushing of food) and deglutination (swallowing) occur
• Salivary Glands


  Endocrine glands that produce saliva containing the enzyme amylase to aid in the digestion of starch
• Epiglottis


  Tissue that serves as a passageway for air and food
• Pharynx


  Chamber that connects the nasal (nose) and oral cavities of the body
• Esophagus

  Where peristalsis (wavelike muscular contraction and relaxation) occurs to move food from the mouth to the stomach
• Stomach


  Serves as a temporary storage area for food and uses mechanical and chemical digestion to break down food
• Esophageal Sphincter

  Prevents stomach contents from re-entering the esophagus
• Fundus


  Bulge found in the upper part of the stomach
• Pyloric Sphincter


  Regulates the passage of stomach contents into the small intestine
• Parts of the Small Intestine

  • Duodenum
  • Jejunum
  • Ileum
• Pancreas


  Secretes a variety of digestive enzymes that break down carbohydrates, proteins, and fats
• Parts of the Large Intestine

  • Cecum
  • Colon
  • Rectum
• Parts of the Colon

  • Ascending Colon
  • Transverse Colon
  • Descending Colon
  • Sigmoid Colon
• Review: Four Functions of Digestive System, Biological Molecules, Two Major Parts of Digestive System, Digestive Organs, Accessory Organs