basic structure of the mammalian GIT

Question 1

function of the headgut

Answer 1

Buccal cavity used for preparation of food for swallowing ( teeth, jaw, saliva, tongue) , analysis of food (taste, texture and temperature) using the toungue; chemical digestion, enzymes. Pharynx, pathway of food, water and air; swallowing reflex.

Question 2

all vertebrates have articulated jaws; except who?

Answer 2

cyclostomes (lampreys, hagfishes)

Question 3

major salivary glands

Answer 3

Parotid, submandibular, sublingual

Question 4

salivary amylase functions in the headgut

Answer 4

breaks 1-4 alpha glycosidic bonds; cannot liberate glucose, doesnt break bonds adjacent to 1-6 glycosidic bonds; produces maltose, oligosaccharides etc.

Question 5

purpose of the crop in birds (expandable sac at the end of the oesophegus)

Answer 5

food storage, some microbial digestion, production of crop milk in some altricial bird ( pigeons)

Question 6

characteristics of foregut fermenters

Answer 6

expanded oesophegeal region of foregut; semi or fully compartmentalized stomach; for retention of food for efficient microbial digestion and absorption. large microbial population.

Question 7

avian stomach is is divided into two compartments

Answer 7

Proventriculus (glandular stomach) and the gizzard (ventriculus and muscular stomach)

Question 8

proventriculus structure

Answer 8

Mucosal glands secreting mucus; deep mucosal glands: oxynticopeptic cells(HCL and pepsinogen)

Question 9

the Gizzard is characteristic of avian species, which other animal groups can house a gizzard?

Answer 9

species of reptiles, fish, annelids, molluscs and arthropods.

Question 10

How does the gizzard aid digestion in the GIT?

Answer 10

mucosal surface is lined with kiolin ( abrasive ‘gizzard teeth’) and chemical digestion.

Question 11

dietary groups of mammal that have a small caecum and a short colon

Answer 11

carnivores

Question 12

which groups of mammal do not have huastra on their large intestines

Answer 12

carnivores and ruminants