GIT anatomy Flashcards
Name some monogastric animals
Cats, dogs, pigs, humans, chickens
Name some ruminants
cattle, sheep, giraffe, goats
Name some hind gut fermenters
horses, rabbits, elephant, ostrich
What are the 4 GIT functions?
- motility, 2. digestion, 3. secretion, 4. absorption
Characteristics of motility?
Mixing ingested material with secretions
Peristalsis
Rate of movement varies bwn feed/spp
Characteristics of digestion?
Breakdown into smaller molecules - mechanical/enzymatic
Aided by secretions
Characteristics of secretion?
Release of useful substances in GIT lumen
Secretions: enzymes, buffers, bile, lubrication, solvent
Characteristics of absorption?
nutrient uptake & use
uses specialised cells lining GIT lumen
passive or active
Pharynx?
Passage for food to oesophagus & air to larynx
Lined by mucous membrane
Oesophagus?
Continuation of pharynx
Passage of food
Regions of pharynx?
naso-, oro-, laryngo-pharynx
Difference in bird oesophagus?
Contains crop (in prey birds) for temp food storage
Monogastric stomach anatomy?
cardiac sphincter, rugae, stomach, pyloric sphincter
How does monogastric digest?
HCl secretions - parietal cells
pepsinogen - chief cells
some bacterial activity in oesophagus
Collectively: Glandular Digestion
What are the 3 stomach glands & their secretions?
Cardiac (mucus), pyloric (mucus & pepsinogen), fundic (mucus, HCl, pepsinogen)
Two stomachs in birds & functions?
proventriculus (adds enzymes) & ventriculus/gizzard (grinding, mixing, contains grit)
Ruminent stomachs?
rumen, reticulum, omasum (forestomach), abomasum (stomach)
Rumen & reticulum characteristics?
Fermentation, chew cud (ruminate), microbes & water (alkaline pH), anaerobic
Omasum characteristics?
Small hard round, filled with muscular laminae (grinds roughage to reduce size, squeezes fluid out, absorbs H2O & FA’s)
Abomasum characteristics?
true stomach, first glandular part of GIT, same function as monogastric stomach
Small intestine characteristics?
Long, narrow, digesta moves thru quickly, mobile (attached by mesentery) Mucous layer covered in villi providing enormous surface area
3 small intestine segments?
Duodenum (near pancreatic & bile ducts), jejunum (longest part), ileum
3 large intestine segments?
Caecum, colon, rectum
Caecum characteristics?
Large comma-shaped sac with ‘blind’ end. Appendix is on end in some species.
Large colon characteristics?
Largest capacity in GIT. Folds into 4 regions (left, right, dorsal, ventral)
Small colon characteristics?
Similar length to large colon, but smaller volume. narrow and more coiled. More free to move (can result in twisted gut)
Differences in GIT volumes (stomach/small intestine/large intestine) hind-gut fermenters vs ruminants?
Horse: Stomach - 10L, SI - 30L, LI - 60L
Cow: Stomach - 70L, SI - 20L, LI - 10L
2 types of rabbit faeces?
- hard round dark 2. caecotrope - softer & larger (essential for digestion of cellulose to soluble nutrients)
What is coprophagy?
Ingestion of faeces
What are the 4 accessory digestive organs?
Salivary glands, liver, pancreas, associated SI glands
Salivary gland characteristics?
Major glands: parotid, mandibular, sublingual
Minor glands: labial, buccal, lingual, palatine
Liver secretion characteristics?
Processing of absorbed nutrients, energy storage, bile secretion, breakdown of exhausted RBC’s.
Bile secretion pathway?
Hepatic ducts + common cystic duct -> common bile duct -> duodenum (Horse has no gall bladder so secretes continuously)
Pancreas secretion characteristics?
Near roof of abdomen (adjacent to duodenum)
2 functions: 1. exocrine (Na bicarb & digestive enzymes via ducts) 2. endocrine (secretes into blood without ducts (insulin, glucagon, somatostatin)
Associated SI glands characteristics?
Brunner’s glands (duodenum - enzymes & mucus), Crypts of Lieberkuhn (between villi on SI - digestive enzymes), Peyer’s patches (submucosa of intestines (esp ileum) - immune function)
