2a Digestive Physiology - Dog and Cat

Question 1

What are some functions of the GI tract?

Answer 1

• digestion
• nutrient and water absorption
• immune function
• secretion
• excretion
• vitamin and mineral balance

Question 2

What is the main difference between the gastrointestinal tract of a dog and cat?

Answer 2

length

Question 3

What is the body length, SI and LI length of a dog?

Answer 3

• body length: 0.75m
• SI: 3.9m
• LI: 0.6m

Question 4

What is the body length, SI and LI length of a cat?

Answer 4

• body length: 0.5m
• SI: 1.7m
• LI: 0.4m

Question 5

What are the 4 structures used to increase gut capacity relative to body weight?

Answer 5

• villi
• microvilli
• coils
• folds

Question 6

What does intestinal length influence?

Answer 6

• retention time of food in the gut

Question 7

What kind of diet does the dog have?

Answer 7

omnivorous

Question 8

What kind of diet does the cat have?

Answer 8

carnivorous

Question 9

For what macronutrients does the lowest capacity exist to digest?

Answer 9

fiber

Question 10

What is the consequence for fermentation?

Answer 10

• digestion of finer
• VFA production
• microbial protein

Question 11

What does the smell and presence of food stimulate?

Answer 11

the salivary glands to produce saliva

Question 12

What are the 4 pairs of salivary glands?

Answer 12

• parotid
• mandibular
• sublingual
• zygomatic

Question 13

What affects the saliva amount and composition?

Answer 13

type of food ingested and its moisture content

Question 14

What do dog and cat saliva lack?

Answer 14

salivary amylase to digest starch

Question 15

Why is the function of saliva important?

Answer 15

• aids in mixing of food and lubrication as many dogs and cats swallow with minimal chewing

Question 16

What is another important function of saliva for dogs?

Answer 16

• evaporative cooling

Question 17

What kind of teeth do dogs have?

Answer 17

• cutting canine teeth for ripping and tearing

- large molars and premolars can grind and chew large or tough pieces of food

Question 18

What kind of teeth do cats have?

Answer 18

• teeth suited for holding and killing small prey animals

- less efficient in chewing and grinding

Question 19

What is the esophagus?

Answer 19

• short hollow muscular tube

- uses peristalsis to move food

Question 20

How does the cell lining of the esophagus help?

Answer 20

• produces mucus

Question 21

What is at the base of the stomach?

Answer 21

• cardiac sphincter

- prevents reflux of food from stomach to lower esophagus

Question 22

What is the stomach and its function?

Answer 22

• a food reservoir that mixes food, regulates flow of digesta to the SI and initiates chemical digestion of protein

Question 23

What is the point of chemical digestion in the stomach?

Answer 23

disrupt 3D structure of food (proteins)

- no digestion of carbs and fats

Question 24

What 2 sections is the stomach divided into?

Answer 24

• proximal and distal sections

Question 25

What is one function of the proximal stomach in dogs?

Answer 25

- proximal expands during temporary food storage allowing dog to eat discrete meals

Question 26

What is gastric secretion influenced by?

Answer 26

- the amount of protein in the meal, the meal volume and hormones

Question 27

What does gastric pH depend on?

Answer 27

- varies depending on the type of meal consumed (buffering capacity of the food)

Question 28

What 4 things is gastric emptying rate controlled by?

Answer 28

- stomach volume - body weight - water intake - diet type

Question 29

Do high density or smaller particles empty more slowly?

Answer 29

high density

Question 30

What is hormonal control of gastric emptying based on?

Answer 30

- maconutrient composition and characteristics

Question 31

What is the average half emptying times for dogs?

Answer 31

72-240 min

Question 32

What is the average half emptying time for cats?

Answer 32

22-449 min

Question 33

What is the role of soluble fibre?

Answer 33

- increases viscosity which slows flow of digesta from stomach to small intestine

Question 34

How is a cat stomach different from a dog stomach?

Answer 34

- cat stomach less important as storage reservoir | - cat stomach simpler and smaller with smaller glandular funds

Question 35

What is the function of the small intestine?

Answer 35

- chemical digestion and absorption of fat, starch, sugar and protein - acidic chyme stimulates secretion of pancreatic juice which increases pH of digesta - chyme missed with enzymes from duodenal mucosa and pancreas - mechanical digestion through peristalsis - villi increase surface area

Question 36

What are the functions of the pancreas?

Answer 36

- exocrine: secretes inactive enzymes and bicarbonate salts into gut - endocrine: secrete hormones into the blood

Question 37

What is the function of the liver?

Answer 37

- production of bile which is stored in gall bladder - bile released when chyme enters SI (gall bladder contracts) - emulsifies dietary fat and activate enzymes to aid in fat digestion - portal vein runs from gut to liver

Question 38

Describe the small intestinal microbiology.

Answer 38

- dog has a simple microbial population - cats may have a greater amount of bacteria - role in preventing pathogenic microbes from colonizing

Question 39

How can transit time of digesta be measured?

Answer 39

- indigestible markers such as chromic oxide

Question 40

How do sugar transport systems in the dog and cat differ?

Answer 40

- cat: sugar transport systems not adaptive to varying levels of dietary carbohydrate - cat amylase about 5% of that in dogs - amino acid transporters in cat are highly adaptable - dog sugar transport systems are highly adaptive to dietary carbohydrates

Question 41

What are the functions of the large intestine?

Answer 41

- absorption of water and electrolytes | - fermentation of dietary fibre and undigested nutrients from the SI

Question 42

Does the large intestine contain villi?

Answer 42

- no

Question 43

What are the 3 parts of the large intestine?

Answer 43

- cecum, colon, rectum

Question 44

What is excreted cecal matter made up of?

Answer 44

- undigested food, sloughed cells, bacteria and endogenous losses - can change depending on type of diet

Question 45

What does bacterial fermentation produce?

Answer 45

- SCFA, lactate, CO2 and hydrogen gas

Question 46

How is the GI tract controlled?

Answer 46

- nutrient flow from intestine to portal vein functions to control enzymes, nutrient transporters, persitalsis

Question 47

What are the 3 mechanisms of GI control?

Answer 47

- incretins - pancreas (enzymes, hormones, bicarbonate) - nervous system

Question 48

What are incretins?

Answer 48

- gastrointestinal hormones

Question 49

What is GIP's cell type?

Answer 49

K

Question 50

What is GIP's location of action?

Answer 50

duodenum, jejunum and ileum

Question 51

What is GIP's primary stimulatory and inhibitory action?

Answer 51

- stimulates: insulin secretion and synthesis | - inhibits: gastric acid secretion, gastric and small intestine mobility

Question 52

What is GIP's stimulus for secretion?

Answer 52

- glucose, AAs and FAs in small intestine | - somatostatin regulates release

Question 53

What is CCK's cell type?

Answer 53

I

Question 54

What is CCK's location of action?

Answer 54

duodenum and jejunum

Question 55

What is CCK's primary stimulatory and inhibitory action?

Answer 55

- stimulates: pancreatic enzyme secretion and gall bladder contraction - inhibits: gastric emptying and secretion and relaxes sphincter of Oddi

Question 56

What is CCK's stimulus for secretion?

Answer 56

- peptides, AAs and FAs in duodenum

Question 57

What is the function of taste and nutrient receptors?

Answer 57

control of intake

Question 58

What is the outcome of control of digested nutrients?

Answer 58

- nutrient utilization and deposition - satiety - feed intake and feeding behaviour