What are the three main body cavities that develop in embryology?

The three definitive body cavities are the pericardial, pleural, and peritoneal cavities. They all originate from the intraembryonic celom, which is initially a single continuous space.

How does the intraembryonic celom form during embryonic development?

It appears in the lateral plate mesoderm during the 4th week, splitting it into two layers: the somatopleuric layer (near ectoderm) and splanchnopleuric layer (near endoderm). The celom has three parts: pericardial cavity, peritoneal cavities, and pericardioperitoneal canals.

What structures partition the intraembryonic celom into separate cavities?

Two key structures are involved: pleuropericardial membranes separate the pericardial and pleural cavities, and the diaphragm separates the pleural and peritoneal cavities.

How does the pleural cavity develop from the intraembryonic celom?

It develops from the pericardioperitoneal canals. Lung buds grow into these canals, enlarging them to form pleural cavities. Pleuropericardial folds project in and fuse to create membranes that separate pleura from pericardium.

What is the peritoneal cavity, and how does it form?

The peritoneal cavity is the largest body cavity, formed by fusion of the lateral limbs of the intraembryonic celom. Initially, it communicates with the extraembryonic celom at the umbilicus, but this connection is lost by the 10th week of intrauterine life.

What is the lesser sac, and how does it develop?

The lesser sac, or omental bursa, is a peritoneal recess behind the stomach. It forms through processes like enlargement of the right pneumoenteric recess, stomach rotation, and ligament formation, including the gastrosplenic and lienorenal ligaments. It communicates with the greater sac via the foramen epiploicum.

Body Cavities Development – Pericardial, Pleural, Peritoneal