Digestive 1

Question 1

Embryonic origin of smooth muscle around digestive tract

Answer 1

splanchnic hypomere mesoderm

Question 2

Describe three adaptations of gnathostome digestive systems from those of agnathans

Answer 2

1. stomach - storage & mechanical digestion
2. pancreas - better chemical digestion
3. longer intestines - better absorption

Question 3

embryonic origin of lining of digestive system

Answer 3

Endoderm: pharynx & alimentary canal

Ectoderm (invagination to STOMODEUM): buccal cavity

Question 4

Define stomodeum

Answer 4

Ectodermal invagination that will eventually for the lining of the buccal cavity

Question 5

Order of processes in digestive system

Answer 5

Ingestion -> (storage) -> propulsion -> mechanical digestion -> chemical digestion -> bacterial digestion -> absorption -> defecation

Question 6

Define food quality

Answer 6

Amount of energy per unit of food & ease/speed of digestion

Question 7

Embryonic origin of buccal cavity lining

Answer 7

Stomodeum (invagination of ectoderm)

Question 8

Describe the digestive system of agnathans, and give reason for why it works

Answer 8

straight tube from mouth to anus with no stomach & short intestine - don’t need to digest & absorb well because food already digested (blood or decaying animals)