Lecture Twenty - Nutrients and digestion II Flashcards
What are animals and plants primarily made up of?
Animals:
Mostly protein.
Easily digestible.
Plants:
Mostly carbohydrates.
Some easily digestible and some not.
Describe mammal dentition.
Carnivore - simple teeth (not many grooves, faces or nooks) and digestive system.
Herbivore - complex teeth and digestive system.
What is the difference in length between herbivores and carnivores?
Carnivores have shorter intestins, where as herbivores have longer more complex intestines.
What is a gizzard?
Gizzard: A muscular, thick-walled part of a bird’s stomach for grinding food, typically with grit.
Carnivores gizzards are smaller and less muscular compared to herbivores gizzards.
Order of food digestion in birds:
Mouth -> Oesophagus -> Crop -> Stomach -> Gizzard -> Intestines -> Anus.
Describe a cows digestive system (ruminant).
Ruminent stomaches contain four compartments: the rumen, the reticulum, the omasum and the abomasum.
Once initially swallowed, the bolus goes to the rumen and the reticulum. Both of these chambers serve as fermentation vats for microorganisms that digest cellulose.
For these two chambers, rumination can occur, which is the regurgitation of the bolus after it is swallowed and fermented.
Rumination allows partially digested plant material to be re-chewed (the chewing of cud), increasing the SA available for microbial attachment.
The bolus is then swallowed again, and moves to the omasum, where water is remove from the bolus.
Finally, the bolus reaches the abomasum, or the true stomach, where it first con acts gastric juice and is further digested by enzymes.
What are forgut and hindgut fermenters?
Foregut fermenters = when fermentation occurs before the stomach.
Complex stomach containing bacteria.
Energy from volatile fatty acids produced by bacteria (by products).
Protein from bacteria.
- Ruminants.
- Colobine monkeys.
Hindgut fermenters = when fermentation occurs after the stomach.
Very efficient teeth and simple stomach.
Cecum and colon containing bateria.
Energy mainly from cell contents.
Protein from cell contest (and bacteria via coprophagy).
- Cecal fermenters:
–> Rabbits and hares.
- Colon fermenters:
–> Humans.
–> Horses.
How do hindgut fermenters such as horses over come this feature of their digestion?
Gain volatile fatty acids from fermentation.
Colen/cecum adapted to act like the small intestine (take up nutrients).
Gain some protein from cell material.
How do hindgut fermenters such as rabbits over come this feature of their digestion?
Coprophagy: Animals who eat their own faeces or dung in order to gain all possible nutrients from the already digested poo/food.
What are enzymatic adaptations for digestion?
Enzymes in the small intestine of birds.
