Digestive System Flashcards
What are the functions of the digestive tract?
Digestion, absorption of food, and elimination of residual waste
What are the main parts of the tubular digestive tract?
Oral cavity, pharynx, Alimentary canal
What are the parts of the alimentary canal?
Esophagus, stomach, intestines, accessory glands, anus
What is the cloacal opening?
A common opening for intestinal, reproductive, and urinary tracts: found in some fish, amphibians, reptiles, birds, and monotremes
How do suspension feeders like protochordates obtain food?
*Water containing plankton drawn into the incurrent siphon via cilia on pharyngeal slits
*Food particles are then trapped in mucus from endostyle and passed to the stomach
What happens to nutrients and waste in protochordates?
*Nutrients are absorbed in the intestine
*Waste is eliminated via the anus and excurrent siphon
How do amphioxus filter food?
*Water and food are drawn into the mouth via cilia on the wheel organ
*Food passes through the pharynx and is trapped by mucus in the endostyle
What role does the hepatic cecum play in amphioxus digestion?
Secretes digestive enzymes and absorbs nutrients
What is the function of the atriopore in amphioxus?
Allows water to exit after passing though gill slits
What is the pathway of waste elimination in amphioxus?
Waste is expelled through anus
Where does digestion take place in amphioxus?
Iliocolonic ring
What characterizes the hagfish digestive system?
*Rasping tongue with 2 pairs of keratinized teeth
*food passes to the pharynx and intestine for absorption
*Waste is expelled through anus
How does the ammocoete larva digest food?
*Muscular pharynx draws in water and food
*Mucus from the subpharyngeal gland traps food
*Food moves to the esophagus, then to the intestine, liver and gallbladder
*Waste expelled through anus
What is the role of the oral disk and keratinized teeth in lamprey digestion?
Used for grasping and cutting away tissue from prey
HAs oral glands that secrete anticoagulants to aid in feeding
How do lampreys create suction to feed?
The velum seals the buccal cavity to generate negative pressure
A vacuum is created as the pharyngeal muscles expel water through gill slits
Describe the lamprey digestive system.
*The pharynx is divided into dorsal esophagus and ventral respiratory tube
*Esophagus leads to a straight intestine with a liver
*Waste is expelled through the anus, opening into the cloaca
What is the function of the oral cavity in gnathostomes?
Provides a passage from the mouth to the pharyngeal cavity and separates the pharyngeal region
What structures separate the oral cavity and pharynx in gnathostomes?
The palatoglossal arch
What structures are associated with the lips in gnathostomes?
Non-mammalian: lips meet at jaw articulation
Mammals: lips extend anterior to jaw forming cheeks
What is the oral vestibule?
It separates teeth and gums from the lips and cheeks
What forms the primary palate in gnathostomes?
Paired bones such as vomer, pterygoids, parasphenoid and palatine
