Digestive System (Gastrointestinal)

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Digestive System (Gastrointestinal)

• Functions of the Digestive system
• Intake and digestion of food
• Absorption of nutrients from digested food
• Elimination of solid waste products
• Accessory Organs of Digestion
• Include the liver, gallbladder,
• and pancreas

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Anatomy

• Structures are divided into two sections
• Upper GI Tract mouth, esophagus, stomach
• Lower GI Tract small intestine, large
• intestine, rectum, anus
• Oral Cavity (mouth)
• Lips form opening to the mouth
• Hard palate anterior portion of roof of mouth
• Soft palate posterior portion of roof of mouth,
  closes off nasal passage during swallowing
• Uvula helps in producing sound and speech

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Upper GI tract Contd.

• Tongue strong and flexible, aids in speech and
  moves food during chewing and swallowing,
  contains papillae which are also known as taste
  buds.
• Teeth 20 baby teeth, 32 permanent teeth four
  kinds
• Incisors
• Canines
• Premolars (bicuspids)
• Molars

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Upper GI tract Contd.

• Parts of a tooth
• Crown the part of the tooth that is visible,
  covered with enamel
• 2. Root holds the tooth securely in the dental
  arch
• Dentin makes up the bulk of the tooth
• Gingiva (gums) surrounds teeth, covers the bone
  of the dental arches, forms the lining of cheeks
• Salivary Glands secretes saliva to moisten
  food, begins digestive process, cleanses the mouth

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Upper GI tract Contd.

• Pharynx (also known as the throat)
• common passageway for food and air
• during swallowing, food is prevented from
  moving
• from the pharynx into the lungs by the
  epiglottis.
• Esophagus
• collapsible tube that leads from the
• pharynx to the stomach
• the lower esophageal sphincter is a muscle that
  controls the flow between the esophagus and the
  stomach.

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Upper GI tract Contd.

• Stomach
• has 3 sections fundus, body, and the antrum
• the pyloric sphincter controls flow from
  stomach into the duodenum of the small
  intestine.

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Lower GI tract

• Small Intestine extends from pyloric sphincter
  to the large intestine in the small intestine is
  where nutrients are absorbed into bloodstream 20
  feet in length has three sections
• Duodenum first section, closest to the stomach
• Jejunum middle section, between duodenum and
  ileum
• Ileum last section, closest to the large
  intestine

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Lower GI tract Contd.

• Large Intestine waste products of digestion are
  processed in the large intestine and excreted
  through the anus has 6 sections
• Cecum pouch that extends from the ileum to the
  beginning of the colon
• Ascending colon travels upward from cecum
• Transverse colon passes right to left toward
  the spleen
• Descending colon travels down
• the left side of abdominal cavity
• Sigmoid colon joins descending
• colon with the rectum
• Rectum last division of the large intestine
• Anus solid waste is passed out of the body
  through the anus

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Accessory Organs of Digestion

• Liver (located in the right upper quadrant)
• removes excess glucose from the bloodstream
• destroys old red blood cells
• removes poisons from blood
• makes some blood proteins
• secretes bile to break down fat
• Gallbladder
• stores and concentrates bile for later use
• Pancreas
• located posterior to the stomach, creates
  pancreatic juices to neutralize stomach acids and
  digestive enzymes to process protein,
  carbohydrates, and fat.

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Definitions
Digestion process by which complex foods are
broken down into nutrients that the body can
use Metabolism all of the processes involved
in the bodys use of these nutrients(building up
and breaking down of body cells) Absorption
process where digested nutrients are taken into
the circulatory system
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Definitions Contd
Mastication also known as chewing, breaks down
food into smaller pieces Peristalsis series of
wavelike contractions of smooth muscles in a
single direction. Chyme semi-fluid mass of
partially digested food that passes from stomach
into small intestine Defecation evacuation or
emptying of the large intestine
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Flow through the Digestive System
You will need to know the order of flow for food
moving through the digestive system on your next
test.
The Language of Medicine, 7th Edition Chabner,
Davi-Ellen Saunders, 2004
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ACTIVITY
How The Stomach Works