The Digestive System

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The Digestive System
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Major Activities

• Ingestion intake of food through the mouth
• Mechanical Processing the physical manipulation
  of food
• Digestion the chemical breakdown of food into
  its building blocks
• Secretion the release of water, acids and
  enzymes from cells

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Major Activities

• 5) Absorption the movement of small molecules
  from the lining of the digestive tract into the
  blood stream
• 6) Defecation the formation and removal of
  feces
• 7) Peristalsis the involuntary muscle
  contractions that move food through the digestive
  tract

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Organs of the Digestive System
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Mouth

• Oral cavity Entrance of d.s., food is chewed
  and chemically digested
• Salivary glands parotid, submandibular,
  sublingal
• Tongue moves bolus (food ball) to back of soft
  palate
• Epiglottis flap of cartilage that covers trachea

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Oropharynx

• Esophagus tube that connects mouth the stomach
• Cardiac Sphincter opening into the stomach

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Stomach

• Stomach stores ingested food, churns food with
  acid, forms chyme
• Pyloric sphincter opening to small intestine,
  controls rate that chyme leaves stomach

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Small Intestine

• Duodenum first section of S.I., 10 inches long,
  c-shaped
• Jejunum most absorption of digested foods
• Ileum absorption of bile salts and B-12

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Large Intestine

• Ileocecal Valve - opening between S.I. and cecum
• Cecum - first part of large intestine
• Ascending Colon transport of waste up
• Transverse Colon - transport of waste across
• Descending Colon transport of waste down
• Sigmoid Colon Entrance into rectum

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Accessory Organs

• Liver produces bile
• Gallbladder - stores concentrated bile
• Pancreas releases enzymes that neutralize chyme

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