Digestive System

Gastrointestinal (GI) Tract-the continuous tube through which food/drink passes through from mouth to anus.

Pathway food follows along the GI Tract:

• Mouth --> oral cavity (food in converted into a bolus) --> pharynx --> esophagus --> stomach (food is changed into liquid form, chyme) --> small intestine --> large intestine --> rectum --> anus.

Functions of the Digestive System

• Ingestion: Eating!
• Secretion: the GI tract secrets approximately 7-L of fluid every day.
• Mixing and Propulsion: alternating contractions and relaxations along the GI tract propel food toward the anus. This ability is termed motility.
• Digestion: mechanical (i.e chewing) and chemical (i.e. breakdown with enzymes) processes that break food down into smaller, usable molecules.
• Absorption: the entrance of nutrients (products of digestion) into the epithelial cells of the lumen (lining of the GI tract).
• Defecation: excretion.

Links!

Digestive System Anatomy

• http://www.tvdsb.on.ca/westmin/science/sbi3a1/digest/digdiag.htm

Digestion Timeline

• http://www.whfoods.com/genpage.php?tname=faq&dbid=16#digestion

Digestive Animation

• http://www.uclan.ac.uk/facs/health/nursing/sonic/scenarios/uclananim/wholebodyzoom.swf

Metabolism Activities

• http://www.wiley.com/legacy/college/boyer/0470003790/animations/organs_processes/organs_processes.htm