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UKCD ANA534 Body Cav
learning objectives for body cavity development
Question | Answer |
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The intra-embryonic coelom will eventually be divided into four body cavities. List them. | Pericardial cavity (1); pleural cavities (2); and peritoneal cavity (1). |
What two partitions must develop to form these cavities? | The diaphragm and the fibrous pericardium. |
How is the pericardial cavity in free communication with the peritoneal cavity? | Through the paired pericardioperitoneal canals. |
What forms the fibrous pericardium? | Two pleuropericardial membranes (sheets of somatic mesoderm) form the fibrous pericardium by growing inward from either lateral aspect of the embryo. |
What three sources fuse to form the diaphragm? | septum transversum, two pleuroperitoneal membranes and dorsal mesentery |
What part does the septum transversum form? | forms the central portion of the diaphragm - including the central tendon |
What part does the two pleuroperitoneal membranes form? | largely responsible for the peripheral regions of the diaphragm, pleura and perioneum that cover its upper and lower surfaces respectively |
What part does the dorsal mesentery of the esophagus forms ? | the crura of the diaphragm. |
Where is the septum transversum formed and what spinal cord levels innervate it? | The septum transversum forms in the neck region by fusion of the third, forth and fifth cervical segments and is therefore innervated by spinal nerves from C3, 4, 5. |
How do the pleural cavities form? | As the lung buds develop, the splanchnic mesoderm covering them is invaginated into the pericardioperitoneal canals. This portion of each canal becomes the pleural cavity on each side. |
When does the respiratory system start to form? | About week 4 |
How does the respiratory system start to form? | a median longitudinal groove (laryngotracheal groove) develops in pharyngeal floor, edges of groove fuse and form a laryngotracheal tube whose lumen is separated from foregut. |
What else occurs in respiratory formation? | A lung bud grows outward from either side of the tube invaginating the intra-embryonic coelom. This part of the coelom forms the pleural sacs around each lung bud. Visceral and parietal pleura then form. |