Download Digestive System PowerPoint

Ms. Bowman
• Functions
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Takes food in
Breaks food down into nutrient molecules
Absorbs nutrients into the bloodstream
Rids the body of indigestible remains
• Organs of digestive system fall into 2 categories
• Those of alimentary canal
• Accessory organs
• Also called gastrointestinal (GI) tract
• Continuous muscular digestive tube that winds through the body
• Functions
• Digests food
• Absorbs nutrients through lining into the blood
• Organs
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Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Anus
• Over 30 ft in length
• The food material in this canal is technically outside the body
because the canal is open to the external environment at both
ends
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Teeth
Tongue
Gallbladder
Salivary glands
Liver
pancreas
1. Ingestion-taking food into the mouth
2. Propulsion-moves food through the alimentary canal
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Includes swallowing and peristalsis (major means of propulsion; involves
alternating waves of contraction and relaxation of muscles in the organ
walls
3. Mechanical Digestion-physically prepares food for chemical
digestion by enzymes
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Includes chewing, mixing of food with saliva by tongue, churning food in the
stomach, and segmentation (mixes food with digestive juices and increases
efficiency of absorption)
4. Chemical Digestion-series of catabolic steps in which food molecules
are broken down into their chemical building blocks
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Food broken down by enzymes
Starts in the mouth and is complete in the small intestine
5. Absorption-passage of digested end products from the GI
tract through the mucosal cells into the blood or lymph
o Small intestine is the major absorptive site
6. Defecation-eliminates indigestible substances from the body
via the anus in the form of feces