Digestive Physiology 1 Flashcards
What are the structures to increase surface area to capacity in the GIT?
- Villi
- Microvilli
- Coils
- Folds
What macronutrient does the dog / cat have the LOWEST ability to digest?
Fiber - need microbes in the gut
What kind of diet does a dog have? Cat
Omnivorous, carnivorous
What are the four pairs of salivary glands
parotid, sublingual, zygomatic, mandibular
What stimulates the salivary glands to secrete saliva?
Presence / smell of food
The type of food and it’s moisture content affect saliva amount and composition
What do dogs and cats lack in their saliva? What is a consequence of this?
Alpha amylase - lack the ability to start starch digestion in the mouth. Also may hinder the ability to detect glycemic index in food.
What features are prominant in dog teeth
lots of molars / pre molars to grind / chew large pieces of food
What features are prominant in cat teeth
Teeth are suited for holding prey, less suited towards grinding
What is secreted in the stomach and what is digested there
HCL and pepsinogen - where protein digestion starts (becomes unfolded due to acidity)
NO carbohydrate or fat digestion in the stomach just carbs
Why are dogs able to eat large discrete meals?
Proximal part of the stomach can expand
What is gastric secretion in the stomach influenced by
Amount of protein in the meal, meal volume, hormones
What affects gastric emptying rate?
Diet composition ( more dense fibers take longer to pass though, decrease passage rate), stomach volume, water intake, body weight High density particles empty more slowly than smaller sized particles Hormonal control based on macronutrient composition and characteristics
Name some exocrine functions of the pancreas
Secretes enzymes, and bicarbonate salts into the gut to establish ph
for example, trypsin, chymotrypsin, inactive enzymes (proenzymes), lipases, amylases, proteases
Endocrine functions of the pancreas?
Secrete insulin / glucagon
What is the role of bile, where is it stored / produced
Produced in the liver, stored in the gall bladder, it emulsifies fat and activates enzymes to digest fats
How can transit time be measured?
Via indigestible markers
Name some differences in SI between cat and dog
CAT: sugar transport system NOT adaptive to varying levels of dietary carbohydrate
Dog: sugar transport systems are HIGHLY adaptable to varying levels of dietary carbohydrates
Also with cats:
Free sugars and complex carbohydrates normally negligible percentage of diet
No energy wasting to change carrier systems
Pancreatic amylase production about 5% of that in dogs
Pancreatic amylase production is relatively nonadaptive in cats
Amino acid transporters are highly adaptable, esp. for arginine
What are the main functions of the LI - how long is transit time approximately for dogs / cats?
absorption of water and electrolytes
Fermentation of dietary fiber and undigested nutrients from the SI
Transit time is about 12 hours
What is excreted fecal material made up of
Endogenous sloughed cells, bacteria, undigested food, endogenous losses
What does bacterial fermenation produce
SCFA, Lactate, CO2, Hydrogen gas (methane)
What are incretins?
Incretin are gastrointestinal hormones- GIP that is glucose dependent insulinotropic peptide and GLP- glucagon like peptide-1 . After feeding GIP is released from K cells of small intestine whereas GLP-1 are released from L cells of large intestine. Both act on beta cells of pancreas and stimulates insulin secretion and this how intestine controls insulin secretion
2 Incretins that are linked to fiber / starch
See intestine, section of pancreas, one incretin highlighted GLP-1 – an incretin (hormone produced) acts on certain amount of glucose in the lumen of the gut in SI food is degraded – think starch / glucose – taste receptors in gut (same as in mounth0 that recognize more glucose and secrete GLP – 1 which goes to the pancreas – which has receptors for GLP-1 (pancreas knows before glucose reaches it_) to start releasing insulin. Role – important signal molecule linking gut to pancreas. – not only nutrients that provide links to organs also hormones that provide link to hormones – part of system pancreas and gut communicate with each other.
What is CCK where is it’s location of action
what is it’s primary action what’s it’s stimulus for secretion
Location of action: Duodenum / jejunum
Primary action: stimulates gallbladder contractions, pancreatic enzyme secretion. Inhibits gastric emptying and secretion / relaxation of the sphincter of odii
Stimulus for secretion is: peptides / AA / FA in the duodenum
What is Gastrin where is it location of action what’s it’s primary action and what is its stimulus for secretion?
Location of action: Gastric antrum / duodenum
Primary action: Stimulates: secretion of gastric acid, pepsinogen and glucagon inhibits: gastric emptying
Stimulus for secretion: peptides / amino acids in the stomach, distension in the stomach
