INGESTION

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INGESTION
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PROCESS

• The digestive tract is normally 6.5 to 9 m long
  in adults.
• Physical digestion begins in the mouth.
• - Food is chewed and formed into a bolus by the
  tongue.

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SALIVA

• Contains amylase enzymes
• -break down the starches (complex carbohydrates)
  to simpler carbohydrates
• Lubricates the food and dissolves food particles
• -Lubrification is necessary for swallowing and
  dissolving the food particles allows us to taste
  our food.

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TEETH

• Also play a role in physical digestion
• Formed from 2 parts the root and the crown

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TEETH
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ESOPHAGUS

• Tube that carries the food from the mouth to the
  stomach.

Bolus stretches the walls of the esophagus
activating peristalsis in the smooth
muscles. These contractions are rhythmic in
nature and involuntary.
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Stomach and Digestion

• Site of food storage and initial protein
  digestion.
• Movement to and from the stomach is regulated by
  sphincters (cardiac and pyloric).
• The stomach is J shaped and can expand to store
  1.5 L of food.
• Millions of cells line the interior of the
  stomach and secrete fluids that aid in digestion
  (gastric fluid or juice).

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GASTRIC FLUID

• Approximately 500 mL is produced following a
  large meal.
• This fluid includes mucus, hydrochloric acid,
  pepsinogens and other substances.
• - Mucus
• - Hydrochloric acid
• - Pepsinogens

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Pepsinogen and Pepsin
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ULCERS

• The normal pH in a stomach is in between 2.0-3.0
  but can approach 1.0
• Ulcers occur when the protective mucous lining
  breaks down and the cell membrane is exposed to
  HCl and pepsin.

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ULCERS

• Peptic ulcers occur when the cells of the stomach
  lining are irritated by acid which increase blood
  flow.
• Most ulcers are linked a bacterium called
  Heliobacter pylori.
• TREATMENT In modern medicine, ulcers are treated
  with a device called an endoscope and lasers.

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