Key Terms
Herbivores
Eat only plants (deer, caterpillars, koalas)
Carnivores
Eat other animals (lions, sharks, spiders)
Omnivores
Eat both plants and animals (humans, bears, crayfish)
Gastrovascular cavity
Single opening; serves as both mouth AND anus
Alimentary canal
Two-opening digestive tube; mouth to anus Bolus: chewed, saliva-moistened food mass ready to swallow Chyme: semi-liquid
Examples
Camels, alpacas
Stomach pH
1.5 to 2.5 (extremely acidic; required for chemical breakdown and killing microorganisms)
They practice cecotrophy
Digest food twice by re-ingesting soft feces called cecotrophes.
Crop
Pouch in the esophagus that stores food before it reaches the stomach.
Cloaca
Single exit for both urine and feces (birds do not have separate openings).
Teeth perform mastication
Mechanical breakdown of food into smaller particles. Saliva produced by three glands: parotid, submandibular, sublingual
Epiglottis
Cartilaginous flap that covers the glottis (trachea opening) during swallowing; prevents food from entering the airway.
Gastro-esophageal sphincter
Ring-like muscle at the stomach end of the esophagus; opens when you swallow; stays closed otherwise to prevent stomach
Chief cells
Secrete pepsinogen (inactive form of pepsin) Parietal cells: secrete hydrogen and chloride ions -> combine to form hydro
Chyme
Semi-liquid mixture of partially digested food and gastric juices; moves from stomach to small intestine through the pyl