Mammalian Digestive Systems Lecture 23

Question 1

What are the common characteristics of mammalian digestive systems

Answer 1

GI Tract

Glandular organs that produce secretions that function in the GI tract

Question 2

The main functions of each region of the GI tract

Answer 2

Foregut functions
- ingestion and storage of feeds
Midgut functions
- mechanical, chemical and enzymatic digestion of feed
- nutrient absorption
Hindgut function
- water and ion re-absorption
- formation, storage, excretion of faeces

Question 3

What are the main stages of food processing?

Answer 3

Ingestion: eating - food mostly consists of proteins, fats and carbohydrates which cannot be absorbed
Digestion - breaking down of food into molecules small enough to be absorbed by enzyme hydrolysis
Absorption - cells of the GI tract absorb small molecule i.e. amino acids, simple sugars and glycerol and fatty acids
Elimination - undigested material is passed out of the GI tract

Question 4

Name the accessory glands of the mammalian digestive system

Answer 4

Salivary gland
Pancreas
Liver
Gallbladder

Question 5

Describe the herbivorous adaptation the in GI tract

Answer 5

Dental adaptations
Stomach is divided into chambers with micro-organisms which secrete cellulase
Gut is elongated as digestion of plant is a difficult process

Question 6

Describe the carnivorous adaptations in the GI tract

Answer 6

More nutrient-dense
Dental adaptations for killing and tearing flesh
Gut is short as meat is easy to digest.

Question 7

What are the two kind of stomachs found in mammals?

Answer 7

Monogastric

Ruminate: four stomach compartments

Question 8

Compare and contrast GI tract structures and functions of herbivores, omnivores and carnivores:

Answer 8

Small intestine:
Less variable among species than stomach and hind gut longer in herbivores than carnivores
Large intestine:
larger in herbivores
Importance for hind gut fermentation dictates variation in structure and size
Some hind-gut fermentation occurs in most species

Question 9

Name the two classifications by the site of fermentation

Answer 9

Pregastric fermentation
- microbial digestion before the host animal’s digestive epithelium
Postgastric fermentation
- microbial digestion after the host animal’s digestive epithelium