Development of the Body Cavity and Lungs

Question 1

Describe the structure of the Trilaminar Embryonic Disc

Answer 1

Three germ layers in the centre, with the outer ectoderm, middle mesoderm and inner endoderm. Above the ectoderm is the amniotic cavity, and below the endoderm is the yolk sac

Question 2

What is the role of the “allantois”?

Answer 2

Helps embryo exchange gas and handle waste

Question 3

What is the embryonic precursor of the diaphragm called?

Answer 3

Septum transversum

Question 4

What is the septum transversum?

Answer 4

Embryonic derivative of diaphragm

Question 5

The Septum Transversum divides the Coelem into..?

Answer 5

Pericardial / thoracic cavity

Peritoneal / abdominal cavity

Question 6

What is the Coelom?

Answer 6

The body cavity

Question 7

Initially, the Septum Transversum develops incompletely on the posterior aspect. The pericardial and peritoneal cavities can therefore communicate via..?

Answer 7

Pericardioperitoneal canals

Question 8

What structure finally seals the posterior aspect of the incomplete septum transversum?

Answer 8

Pleuropericardial folds

Question 9

The failure of the Pericardioperitoneal canals closing leads to..?

Answer 9

Congenital Diaphragmatic Hernia

Question 10

What happens in a Congenital Diaphragmatic Hernia?

Answer 10

Failure of the pericardioperioneal folds closing

Question 11

What is Eventration of the Diaphragm?

Answer 11

An abnormal elevation of the diaphragm, causing compression of the lung. Caused by muscle fibre aplasia