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2. Functions of the Digestive System and Organs of the Gastrointestinal tract
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3. The Digestive System Functions
Ingestion- taking in food
Digestion- breaking food down
Absorption- nutrients into the bloodstream
Defecation—elimination of indigestible waste
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4. Organs of the Digestive System
Two groups:
Alimentary canal (gastrointestinal or GI tract)— continuous, coiled, hollow tube (aka gut)
These ingest, digest, absorb, defecate
Accessory digestive organs
Includes teeth, tongue, salivary glands, pancreas, liver, gall bladder
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5. Mouth (oral cavity) Parotid gland Sublingual gland Tongue
Figure 14.1 The human digestive system: Alimentary canal and accessory organs.
Mouth (oral cavity)
Parotid gland
Sublingual gland
Tongue
Salivary glands
Submandibular
gland
Pharynx
Esophagus
Stomach
Pancreas
(Spleen)
Liver
Gallbladder
Transverse colon
Duodenum
Descending colon
Small
intestine
Jejunum
Ascending colon
Ileum
Large intestine
Cecum
Sigmoid colon
Rectum
Appendix
Anus
Anal canal

6. Organs of the Alimentary Canal
a continuous, coiled, hollow tube (about 30ft)
runs through the ventral cavity from stomach to anus:
Structures include:
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Anus
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7. Functions of the Mouth Mastication (chewing) of food
Tongue mixes masticated food with saliva
initiates swallowing
Taste buds are specialized epithelial cells called gustatory cells
Contain taste receptors
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8. Figure 14.2b Anatomy of the mouth (oral cavity).
Upper lip
Gingivae
(gums)
Hard palate
Soft palate
Uvula
Palatine tonsil
Oropharynx
Tongue
(b)

9. Pharynx Food/fluid moves from the mouth into the:
Oropharynx
Laryngopharynx
Peristalsis: the mechanism that propels food and fluid through these parts of the pharynx
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10. Figure 14.2a Anatomy of the mouth (oral cavity).
Nasopharynx
Hard
palate
Soft palate
Oral
cavity
Uvula
Lips (labia)
Palatine tonsil
Vestibule
Lingual tonsil
Oropharynx
Lingual
frenulum
Epiglottis
Tongue
Laryngopharynx
Hyoid bone
Esophagus
Trachea
(a)

11. Esophagus (Gullet)
Runs from pharynx to stomach through the diaphragm (about 10 inches long)
Relies on peristalsis to move food and fluids to the stomach
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