Body cavities

Question 1

Which folding is responsible for the formation of cavities? Which organs are going to develop in them?

Answer 1

1. Lateral folding:
   Resposible for the intraembryonic cavities
2. Cephalocaudal folding

Question 2

Which cavities are formed? Give an overview of each.

Answer 2

1. Thoracic cavity
2. Pleural cavity
3. Pericardial cavity
4. Diaphragm
5. Abdominal cavity
6. Pelvic cavity

The diaphragm is also called septum transversum, since it divides the thorax from the abdomen. It is a layered structure:

• ST
• Pleuroperitoneal membranes
• mesoderm
• esophageal mesenchyme

The pleuropericardial cavity at 5/6 weeks folds, divideing itself into:
- deifinite pericardial cavity
- pleural cavity
The internal lining of this cavity is formed by parietal/somatic mesoderm.