Specialised digestive systems

hindgut fermenters

herbivores that eat mostly high fibre plant material

have adapted digestive systems as fibre is hard to digest

how are hindgut fermenter digestive systems adapted?

digest most food in cecum and at the start of the large intestine - where there are large numbers of microbes to ‘ferment’ the food

domestic rabbit digestive system diagram

bird digestion

1. Use their tongue to move food to the back of their mouth where it is swallowed (do not chew)

2. food moves from oesophagus to the crop (temporary storage area)

3. food passes to the proventriculus where digestive enzymes and HCl are added

4. food moves to ventriculus (gizzard) where it is mechanically digested

5. where the small and large intestines join, there are two ceca (pouches) where some water is reabsorbed and the food is fermented

6. the cloaca, at the end of the digestive system, mixes digestive and urinary waste and expels them as one substance

do birds chew?

no

how do birds swallow food?

use tongue to move food to back of mouth

crop function

temporary storage area

what happens in the proventriculus?

digestive enzymes and HCl is added

another name for the ventriculus

gizzard

ventriculus function

mechanically digests food

what happens at the ceca in bird digestion?

some water is reabsorbed and food is fermented

function of cloaca

mixes digestive and urinary waste and expels them as one substance

ruminants

specialised foregut fermenters - stomach consists of four chambers

parts of a ruminant stomach

rumen, omasum, abomasum, reticulum

ruminant digestion process

1. Rumen - fermentation occurs here in an anaerobic environment where microbes secrete enzymes e.g. cellulase to breakdown cellulose. Saliva helps ensure there is a suitable environment for micro-flora (bacteria) to survive. Reticulum aids the rumen and helps form undigested feed into cud. Retro (reverse) peristalsis allows feed to be brought back up to allow it to be mechanically broken down by chewing and then swallowed, allowing further digestion

2. Reticulum - filters food in rumen, allowing only sufficiently broken down parts to move onto the omasum

3. Omasum - some water and salts are absorbed, then remaining matter is passed to abomasum

4. Abomasum - aka true stomach, digestive enzymes and acid are added

what happens in the rumen in ruminant digestion?

fermentation

micro-flora

bacteria

reticulum function in ruminant digestion

filters food in rumen

omasum function in ruminant digestion

some water and salts are absorbed

abomasum function in ruminant digestion

digestive enzymes and acid are added

which stomach compartment in ruminants is also known as the true stomach?

abomasum

cow digestion diagram

examples of ruminant animals

buffalo, cattle, goat, sheep, bison, yaks, water buffalo, antelope, deer, camels, giraffes, alpacas, llamas, kangaroos and other Australian marsupials

antelope digestive system diagram

horse digestive system diagram

examples of hindgut fermenters

rabbits, guinea pigs, hares, rodents, horses, rhino

coprophagy

consumption of faeces, seen in animals like rabbits. It allows them to re-indigest nutrients and vitamins produced by gut microbes, enhancing nutrient absorption. This is essential to obtain maximum nutrition from their diet. Preventing this can lead to nutrient deficiencies and digestive issues, as these animals rely on this process to maintain their health

bird digestion diagram

enzyme

groups of molecules that help speed up chemical reactions

what is amylase produced by?

salivary glands and pancreas

structure of enzymes

subunits of amino acids

active site to take in substrate and break down

hepatocytes

liver cells