herbivore digestion Flashcards
give two reasons why a herbivore’s gut is longer than a carnivore’s gut
- plant material (cellulose cell walls) needs more time and enzyme action for it to be broken down
- more space is required to accommodate the bulkier plant material
what is a monogastric digestive system and which animals have one
a simple stomach, humans, chickens, rabbits, swine
what is a ruminant digestive system and which animals have one
a complex stomach, sheep, cows and goats
in sheep and cows, how is the stomach divided and what are the names
divided into 4: rumen, reticulum, omasum, abomasum
what do mammals have that breaks down cellulose cell walls
cellulase secreting bacteria (the mammal doesn’t secrete the cellulase itself)
describe what happens in the rumen in a ruminant digestive system
it contains mutualistic bacteria, produces the products of fermentation (beta glucose and fatty acids) which act as an energy source
describe what happens in the reticulum in a ruminant digestive system
(from rumen, food passes into the reticulum) then is regurgitated for “chewing of the cud” then is re-swallowed and passed into the omasum
describe what happens in the omasum in a ruminant digestive system
food is churned = allows further fermentation, then passed into the abomasum
describe what happens in the abomasum in a ruminant digestive system
produces typical acid and enzymes produced by mammalian stomachs, any bacteria are killed then digested
what can bacteria do in a ruminant digestive system
they can build up bacterial proteins from non-protein nitrogen present in the grass or stomach
where is the OH group on a beta glucose
above carbon 1
give features of the rumen
ferments cellulose, absorbs organic acids, continually contracting, produces CO2 and CH4, pH is close to neutral (6/7), contains large protozoa
give features of the reticulum
smallest compartment, catches dense and heavy feed for later rumination, contracts for regurgitation
give features of the omasum
third compartment, globe shaped, lining called ‘many piles’, reduces to feed particle size, absorbs water and dries out ingesta, absorbs volatile fatty acids
give features of the abomasum
‘true stomach’, secretes HCl and enzymes for chemical digestion, reduces pH to 2.5 (acidic) = dissolves minerals, kills rumen bacteria, breaks down proteins. passes on ingesta onto the small intestine (to be absorbed)
how is the digestive system different in rabbits compared to cows/sheep?
the cellulase secreting bacteria are found in the caecum (large intestine) and most nutrients are absorbed in the small intestine - rabbits must re-ingest the food to absorb the nutrients
