comparative GIT in domestic animals SDL

Question 1

what are the main functions of the GI tract

Answer 1

• grab and physically break down food
• swallowing and transportation of bolus
• secretion of digestive juices
• digestion by enzymes
• absorption of nutrients
• absorption of water, ions, microbial digestion of remaining CHO and proteins
• excretion of waste products
• production from accessory organs

Question 2

what is the headgut

Answer 2

oral cavity
receives ingested material and breaks down

Question 3

what is the foregut

Answer 3

esophagus and stomach
- conducts sotres and digests. may also ferment

Question 4

what is the midgut

Answer 4

small intestine
- digests and absorbs nutrients

Question 5

what is the hindgut

Answer 5

large intestine
- absorbs water, vitamin production, ion balance and storage of feces.
- fermentation in herbivores

Question 6

why does the small intestine have the least variation between species

Answer 6

essential role in nutrient absorption

Question 7

discuss the location of the duodenum in all mammals, reptiles and birds

Answer 7

• ALWAYS on the right hand side of the abdomen
• ALWAYS has a loop
• ALWAYS contains part of the pancreas between the limbs of the loop

Question 8

what is a herbivore

Answer 8

eats grass or related vegetation
- digestion by microbes

Question 9

what is an omnivore

Answer 9

eats fruit, vegetation, roots and animal source nutrients
- wide variation in GIT structure

Question 10

what is a carnivore

Answer 10

eats animal source nutrients (muscle, fat, blood internal organs)
- eats quickly
- has large stomach

Question 11

discuss the general carnivore GIT

Answer 11

• large stomach
• vomit indigestibel bones and cartilage
• short GI tract, most digestions occurs before end of small intestine
• relies on enzyme digestion (large livers)
• relatively smaller large intestine

Question 12

what are the 2 types of horbivore digestion

Answer 12

• foregut fermentation: complex stomach pouches - sacs or rumen
• hindgut fermenters with simple stomachs (horses, rodent, rabbit)

Question 13

what are the advantages and disadvantages of grass fermentation

Answer 13

advantages:
- rough course feed can be eated
- microbial fermentation delivers valuable nutrients
- microbial action produces valuable proteins for digestion
- microbial digestion produces vitamin K and B vitamin complex

disadvatages:
- grass low energy diet, contains silicates which wear teeth enamel quickly
- vertebrates do not have innate cellulases
- microbial fermentation digest is essential (to to 1/2 fibre in grass cannot be digested in horses without it)
- no diet alternatives - starve if no grass

Question 14

discuss the esophagus

Answer 14

• connects the pharynx to the stomach
• upper aspect runs midline,and passes to the left side as approaches thoraic inlet
• dorsal to trachea at thorax moves back to midline
• runs in mediastinum
• passes through esophgeal hiatus of diaphragm
• terminates/enters at the cardia of the stomach
• wall is thick at narrowest diameter and thin and widest
• becomes thicker from cranial to caudal
• capable of massive expansion to accommodate food boluses
• wall is 3 layered: connective tissue aadventitia (outer), muscular layer and mucous membrane
• striated muscle at pharynx initially
• ## smooth muscle distally