Lab 8: Digestive System

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Lab 8 Digestive System
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Announcements

• Exams
• Lab notes will be on reserve in library and on
  the web

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Goals of the Digestive System

• Extract nutrients from food
• Transform nutrients into useful forms
• Ex- oreo glucose
• 3. Absorb nutrients and distribute them where
  they are needed

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Functions of the Digestive System

• Ingestion intake of nutrients
• Digestion breakdown of large particles into
  smaller ones
• Absorption uptake of nutrient molecules
• Defecation elimination of undigested residues

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Actions of the Digestive System

• 1. Motility
• Breaks up food
• Moves food through the GI tract (Peristalsis)
• Mixes with digestive enzymes
• Secretion
• Release of enzymes and hormones for chemical
  digestion and regulation
• Membrane Transport
• - Absorption of nutrients from the tissues by
  the blood and lymph for transport

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Stages of Digestion

• Mechanical physical breakdown of food
• Chemical digestive enzymes hydrolyze food
  particles to break larger molecules into smaller
  ones
• Some nutrients are absorbed with out digestion
• Vitamins, minerals, cholesterol, water

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Anatomy of the Digestive System

• Oral Cavity
• Pharynx
• Esophagus
• Stomach
• Pyloric Sphincter
• Small Intestine
• Large Intestine

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Accessory Organs

• Teeth
• Tongue
• Salivary Glands

• Liver
• Gall Bladder
• Pancreas

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Oral Cavity

• Functions
• A. Ingestion cheeks lips and tongue mobilize
  food
• B. Digestion
• Mechanical
• Mastication
• Chemical
• 3 salivary glands
• Digests some starches and fat

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Pharynx

• Motility pharyngeal constrictors force food
  down during swallowing

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Esophagus

• www.mywebmd.ca.com

• Straight muscular tube about 1 foot long
• Motility muscular contraction moves food
  towards stomach

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Heartburn and the Esophagus

• Heartburn,