Digestive system Flashcards
What are the five primary functions of the digestive system?
Ingestion, Mastication, Breakdown of food, Absorption, Elimination of waste.
What are the four types of digestive systems in animals?
- Ruminant foregut fermenters (e.g., cattle, sheep)
- Nonruminant foregut fermenters (e.g., hamsters, rats, hippos)
- Hindgut fermenters (e.g., horses, rabbits)
- Autoenzyme-dependent digesters (herbivores & omnivores)
What is the difference between primary and accessory digestive organs?
Primary organs form the alimentary canal, while accessory organs aid digestion but do not directly form the digestive tract
What are the primary digestive organs?
Mouth, Pharynx, Esophagus, Stomach, Small intestine (duodenum, jejunum, ileum), Large intestine (colon, rectum, anus)
What are the accessory digestive organs?
Salivary glands, Liver, Gallbladder, Pancreas, Teeth, Tongue
What are the functions of saliva? (Mouth and Oral Cavity)
Early digestion, lubrication, antimicrobial activity (contains amylase)
What are the six steps of digestion?
- Ingestion
- Propulsion (swallowing & peristalsis)
- Mechanical digestion
- Chemical digestion
- Absorption
- Elimination
How do lips vary between species?(Mouth and Oral Cavity)
- Horses/sheep: soft & flexible
- Cattle: stiff & less mobile
- Cats: small & less mobile.
What is the function of the tongue in digestion? (Mouth and Oral Cavity)
Moves food in the mouth, contains papillae for food manipulation and taste detection
What are mechanical papillae? (Papillae of the Tongue)
Assist in food manipulation and movement
(e.g., Filiform - grip meat, Conical - grinding, Marginal - aiding in suckling)
What are gustatory papillae? (Papillae of the Tongue)
Contain taste buds that detect different taste stimuli
(e.g., Fungiform - sweet/salty, Foliate - found in ruminants, Vallate - large & V-shaped in omnivores)
What is the function of teeth in digestion? (Teeth and Mastication)
Increase surface area of food for enzymatic action.
How do teeth types differ in function? (Teeth and Mastication)
- Incisors: Cutting/Nibbling (sharp in herbivores, shorter in carnivores)
- Canines: Tearing/Holding (long in carnivores, reduced in herbivores)
- Premolars: Grinding/Crushing (flat in herbivores, pointed in carnivores)
- Molars: Tough food grinding (varies by diet).
What are the two classifications of teeth? (Teeth and Mastication)
- Brachydont (low crowned) : Minimal grinding (e.g., dogs).
- Hypsodont (high crowned) : Constant grinding (e.g., herbivores like horses & ruminants).
What is the function of the pharynx? (Pharynx and Esophagus)
A muscular tube that transports food from the mouth to the esophagus and prevents entry into the respiratory tract
What is the role of the epiglottis? (Pharynx and Esophagus)
Directs food into the esophagus and prevents choking by covering the trachea during swallowing
What is the function of the esophagus? (Pharynx and Esophagus)
A musculomembranous tube that passes food (bolus) to the stomach without secreting enzymes
What are the four layers of the stomach? (Stomach: Simple vs. Ruminant)
Mucosa, Submucosa, Muscularis, Peritoneum (serosa)
What are the functions of the simple stomach? (Stomach: Simple vs. Ruminant)
Protein digestion, food storage, regulation of digestion rate
What are the three glandular regions of the stomach? (Stomach: Simple vs. Ruminant)
- Fundic: Contains gastric glands.
- Pyloric: Produces mucous.
- Cardiac: Small region producing mucous.
What are the five cell types in the gastric glands? (Stomach: Simple vs. Ruminant)
- Surface mucous cells (produce mucous).
- Neck mucous cells.
- Parietal cells (produce HCl).
- Chief cells (produce pepsinogen).
- Neuroendocrine cells (produce gastrin & histamine).
What are the four compartments of the ruminant stomach? (Ruminant Stomach)
Rumen, Reticulum, Omasum, Abomasum
What happens in the rumen? (Ruminant Stomach)
Fermentation of fibrous plant materials; microbial digestion occurs
What happens in the reticulum? (Ruminant Stomach)
Regurgitation for re-chewing; also known as the “honeycomb” stomach
