Digestive System
• https://www.youtube.com/watch?v=_QYwscA
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A.K.A
• “GI” System
• Alimentary or digestive tract
Functions
• Carries food for digestion
• Prepares food for absorption
• Transporting waste for elimination
“The journey”
• Begins in the mouth
– Broken down mechanically and chemically
• Mastication-chewing
• Digestive enzymes-speed up chemical reaction
• Proteins amino acids; complex sugarssimple sugars; large fat
moleculesfatty acids, triglycerides
– Absorption
• Blood stream
• Walls of small intestine
– Fatty acids and triglycerides are absorbed in the small intestine
– Elimination
• Solid waste, passed from body
• Feces collects in large bowel and exits through the anus
Mouth
“Oral cavity”
• Hard palate- roof of the mouth
• Muscular soft palate
– Posterior to hard palate
– Separates mouth from throat
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Pharynx
Rugae-irregular ridges
Uvula-aids in production of sound and speech
Tongue (mastication, deglutition)
Tonsils (lymphocytes)
Gums
Teeth-32 permanent
Three pairs of salivary glands-produces saliva, containing digestive
enzymes
– Parotid, submandibular and sublingual
Pharynx
• Muscular tube
• Passageway for food and air
• Epiglottis-prevents food from entering trachea
Esophagus
• Pharynxstomach
• Aids in swallowing
• Peristalsis-involuntary contraction moving
food through GI tract
Stomach
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Fundus-top portion
Body-middle portion
Antrum-lower portion
Sphincters
– Cardiac, esophagusstomach
– Pyloric, allows food to exit
• Rugae-irregular ridges
Small Intestine
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Pyloric sphincter  large intestine
20 feet long
Villi-microscopic projections; aid in digestion
Three parts
– Duodenum
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1 foot long “12 inch”
Receives food from stomach
Receives bile from liver and gallbladder
Receives pancreatic juice from pancreas
– Jejunum
• 8 feet long
• Connects with 3rd section
• “empty”
– Ileum
• 11 feet long
• Attaches to large intestine
• “to roll”
Large Intestine
• Ileum  anus
• Four parts
– Cecum
• Right side connected by ileocecal sphinter
• Vermiform appendix hangs from cecum
– Colon
• 5 feet long
• 3 divisions
– Ascending colon, cecum  undersurface of liver
– Transverse colon, horiz. To spleen then turns down
– Descending colon, downward portion
• Sigmoid colon
• Rectum
Liver
• Located in RUQ
• Bile
– Emulsification-breaking apart of fat globules so pancreas
can digest
• Continuously released from liver
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Keep glucose levels normal
Removes excess glucose, glycogenesis
Converts glycogen into glucose
Converts proteins and fats into glucose, gluconeogenesis
Removal of poisons from the blood
Gallbladder
• Under liver
• Stores and concentrates bile for later use
Pancreas
• Exocrine gland
• Produces amylase and lipase-enzymes that
aid in digestion
• Secretes insulin
– Insulin is needed to release sugar from the blood
to be used by cells in the body
Digestive System Diagram
4/21 Assignment!
• Pgs. 484-486 Combining forms (write in your
notes)
• Check abbreviations with the textbook