Download The Digestive System

The Digestive System
Lesson 1:
The Digestive System
Digestive System
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Purpose:
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Digest food
Process food
Eliminate waste products
Three main functions:
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Digestion
Absorption
Elimination
Label that System
Organs of the Digestive System
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The Tube:
 Mouth and teeth
 Pharynx
 Esophagus
 Small intestine
 Large intestine
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The Saclike Organ:
 Stomach
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Accessory Organs:
 Salivary glands
 Gallbladder
 Liver
 Pancreas
Organs of the Digestive System
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The “Tube”:
 Mouth and Teeth
 Pharynx
 Esophagus
Organs of the Digestive System
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The Tube
(continued):
 Small intestine
 Large intestine
Organs of the Digestive System
 The
Saclike Organ:
 Stomach
Organs of the Digestive System
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Accessory Organs:
 Salivary Glands
Gallbladder
 Liver
 Pancreas
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Fx of the Digestive System
Digestion
 Process of breaking down food
 Occurs in the mouth and the stomach
 chemicals released by accessory organs
 Absorption
 Occurs in intestines
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Functions of the Digestive System
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Elimination
 Process of removing waste from the body
 Occurs in large intestine
Structures of the Mouth (Oral Cavity)
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Tongue
Teeth
Gingivae (gums)
Salivary glands
The Tongue
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Papillae (elevations) and taste buds are located on the
surface of the tongue
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Sweet
Sour
Salt
Bitter
Umami
The Pharynx
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Lies posterior to the mouth
Beginning of the esophagus
Also opens to the trachea
The Esophagus
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Tube leading from the pharynx to the stomach
Carries food to stomach
About 10 inches long
Wavelike muscular contractions called peristalsis move
food to the stomach
The Stomach
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Hollow, saclike organ
Can hold 1 – 1.5 liters
Secretes chemicals that aid in digestion
Processes food into a semiliquid state (chyme)
Prepares food for further digestion and absorption in the
small intestine
How does this system work?
Anatomy of the Stomach
The Stomach
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Muscular Organ:
3 parts:
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Fundus (upper)
Body (main)
Antrum (lower)
The Stomach (cont)
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Stomach lining:
 Mucosa lining
 Rugae
 Glands
 hydrochloric acid
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Chyme:
 Mixture of gastric
juices and semidigested food
Sphincters of the Stomach
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Sphincters are:
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Muscular valves
Allow flow of food in single direction
Sphincters of the Stomach
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Lower esophageal (also
called cardiac) sphincter:
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Between the esophagus
and the top of the
stomach
Keeps food from backing
into the esophagus
Sphincters of the Stomach
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Pyloric sphincter:
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Between stomach and
small intestine
Allows small amount of
chyme into intestines at a
time
The Small Intestine
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Tube about 21 feet long
and 1inch in diameter
Attaches to the stomach
at the pyloric sphincter
Ends at the ileocecal
orifice
Gross Anatomy of the Small Intestine
The Large Intestine
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Begins at the ileocecal orifice
About 5 feet long and 2.5 inches in diameter
Minimal digestion occurs
Sections of the Large Intestine
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Cecum
 Pouch, about 3 inches long
 Appendix
Colon
 Ascending colon
 Transverse colon
 Descending colon
 Sigmoid Colon
Rectum and Anus
 Eliminate waste
The Accessory Organs
Salivary Glands
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Produce saliva
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Secreted into mouth
Contains amylase
optimal pH
Mixes with food
Produces a soft mass called a bolus
Begins of digestion
The Liver
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Largest glandular organ
metabolism of:
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Carbohydrates
Fats
Proteins
Stores iron and several vitamins
Detoxifies
Products of the Liver
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Bile*
Fibrinogen and Prothrombin
Heparin
Blood proteins
The Liver
The Gallbladder
sac below the liver
 Stores bile
 Concentrates bile
 Gallstones can form
(cholelithiasis)
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The Gallbladder
The Pancreas
Produces digestive
enzymes
 endocrine function
 Secretes insulin and
glucagon
 Regulates blood
sugar levels
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Medical Specialists
Bariatrics
Dentist
Gastroenterologist
Orthodontist
Internist
Proctologist