Flashcards in Digestive 2 Deck (24):
What adaptation to (most) Osteichthyes have to increase surface area for digestion & absorption?
Pyloric ceca, at junction of stomach and duodenum
Describe ruminants' stomach
Digastric - 2 main chambers:
Rumen - initial storage & foregut fermentation (helps break down cellulose to simpler carbs, fatty acids, amino acids, peptides)
Abomasum - reached after regurgitation & rechewing, used for chemical & mechanical digestion like a monogastric stomach (+ helps recover some bacteria & nutrients)
What are the component(s) of the hindgut?
Caecum, large intestine
What happens to material digested in the caecum?
Either re-enters ileum for absorption, or excreted as semi-solid feces and reconsumed (because small intestine has the absorptive surface, so want to go through there)
Who has a spiral valve?
non-teleost fishes (Chondrichthyes, Sarcopterygii, non-teleost Actinopterygii)
Describe rugae & their function
Folds in stomach, allow expansion without distension
Function of taste sense in buccal cavity
Assess food quality
Define monogastric stomach
Stomach is 1 connected chamber
What comprises the midgut?
What is the structure of the caecum?
Blind-end chamber at small/large intestine junction, with high surface area
Functions of stomach
- food storage
- glandular secretions (HCl, enzymes) for chemical digestion
- mechanical digestion
What kind of stomach do most animals have? Who are the exceptions?
Archosaurs: proventriculus & gizzard
What is the function of the small intestine, and how is it adapted for this?
Chemical digestion (esp anterior) - bacteria to help (esp w/cellulose) & provide nutrients; secretions + from pancreas, bile; longer if lower quality food
Absorption (esp posterior) - thin epithelium is easy to cross; v. high SA by plicae -> villi -> microvilli (brush border)
Function of the large intestine
- consolidates undigested material
- prepares for defecation
- specifically reabsorbs remaining water, even without nutrient uptake creating an osmolar gradient
Function of esophagus
- transport food to stomach
- keep water out of stomach
Secretions found in buccal cavity? (content & where they are made)
- mucus, digestive enzymes, toxins/anticoagulants/analgesics
- from salivary glands
Describe the stomach in archosaurs
Proventriculus - glandular stomach
Gizzard - grinding stomach (may contain rocks or sand)
What comprises the foregut?
Esophagus, stomach (+ crop, if present)
What are pyloric ceca & who has them?
Pouch at junction of small intestine & stomach for DIGESTION & ABSORPTION, NOT fermentation; in most osteichthyes
Function of the caecum & how it accomplishes it
- cellulose digestion
- lots of bacteria to do hindgut fermentation; lots of surface area
What are the two functions of the buccal cavity?
Breathing, eating (structure is a compromise)
What adaptation do non-teleost fishes (Chondrichthyes, Sarcopterygii, non-teleost Actinopterygii) have to increase small intestine surface area?
Who is the large intestine particularly important in?
Species in dry environments that must conserve water - large intestine is specialized for water reabsorption