Embryology (Body Cavity Development)

Question 1

Diaphragm Development

Answer 1

1. Septum Transversum - primordium of the central tendon of the diaphragm
2. Paired Pleuroperitoneal Folds - merges with septum transversum to close off the pericardioperitoneal canals
3. Dorsal Mesentery of the Esophagus - forms the crura of the diaphragm
4. Body - forms peripheral portions of the diaphragm

Question 2

Lung Development

Answer 2

• Comes from ventral gut tube

Question 3

Falciform Ligament

Answer 3

• Joins liver to anterior abdominal wall

Question 4

Intraembryonic Coelom

Answer 4

• Forms adult body cavities
• Pericardial, Pleural, & Peritoneal Cavities

Question 5

Phrenic Nerve

Answer 5

• Innervates diaphragm
• Moves to L1 during week 8

Question 6

Visceral/Splanchnic vs. Parietal/Somatic Layer of Mesoderm

Answer 6

Visceral - closest to the organs

Parietal - closest to body wall

Question 7

Lesser Omentum

Answer 7

• Joins liver to stomach and upper duodenum

Question 8

Lateral/Transverse Folding

Answer 8

• Brings peritoneal cavities verntrally
• Somatic & Splanchnic Mesoderm get bigger
• Pericardial Cavity & Heart Tube move ventrally

Question 9

Congenital Diaphragmatic Hernia

Answer 9

• Herniation of abdominal contents into pleural cavity
• Caused by failure of pleuroperitoneal folds to develop
• Tends to occur on left side due to the large liver on the right
• Can cause lung hypoplasia & cardia compression

Question 10

Dorsal Mesentery

Answer 10

• Suspends gut
• Routes for blood vessels, nerves, & lymphatic vessels to reach the gut

Question 11

Pleuropericardial Folds vs. Pleuroperitoneal Folds

Answer 11

Pleuropericardial - separates pericardial cavity from pleural cavity (lung location)

Pleuroperitoneal - separates abdominopelvic cavity from sortral pleural cavities