Q5 - Vertebrate Embryology

Question 1

What is the yolk sac membrane in a chicken egg?

Answer 1

A membrane that extends out from the gut and enveloped the yolk

Question 2

What are the roles of the yolk sac in a chicken egg?

Answer 2

Transfer of nutrients from yolk to embryo, and is the primary respiratory membrane in the early stages of development

Question 3

What structure is the yolk sac membrane in a chicken egg formed from?

Answer 3

Area opaca

Question 4

When does the yolk sac membrane develop in a chicken egg?

Answer 4

Between 12-48 hours after fertilisation

Question 5

What is the chorioallantois in a chicken egg?

Answer 5

Fusion of the chorion and allantois against the inner surface of the egg shell

Question 6

What is the chorion in a chicken egg?

Answer 6

An extension of the amnion that forms the outer layer of embryonic tissue

Question 7

What is the allantois in a chicken egg?

Answer 7

Balloon-like structure that extends from the hind gut and acts as waste storage

Question 8

What are the roles of the chorioallantois in a chicken egg?

Answer 8

Main respiratory membrane for most of development, waste storage and calcium absorption from shell

Question 9

When does the chorioallantois develop in a chicken egg?

Answer 9

Fuse at 6-7 days

Question 10

What are the main similarities between the chorioallantois and yolk sac membrane in a chicken egg?

Answer 10

Both provide some form of resource for the embryo (nutrients, oxygen, calcium), with both acting as respiratory membranes at different points in development

Question 11

What are the main differences between the chorioallantois and yolk sac membrane in a chicken egg?

Answer 11

They both develop at different times, with the yolk sac being developed sooner as the embryo’s internal nutrient stores will only last 2 days without access to yolk

The chorioallantois can afford to be developed later