(3) Formation Of The Body Cavity (Keim) Flashcards
What weeks are embryonic development occuring?
3-8
What events are occuring during embryonic development?
Growth
Morphogenesis
Differentiation
When does folding of the embryo occur?
Week 4
Within what plane do the head and tail folding occur?
Median plane
Describe when and where the heart can initially be seen:
Heart can be seen in front of the oropharyngeal membrane
in the EARLY 4th week
What is the septum transversum going to become?
The diaphragm
Describe the folding relationship between the developing heart and the septum transversum
The septum transversum flips under the heart
This causes final location UNDER THE HEART
The foregut gives rise to:
Some GI Structures
The _______ overgrows the heart and septum transversum
Forebrain
The ______ overgrows the cloaca and connecting stalk
Forebrain
During week 4, describe a major communication event:
Intraembryonic coelom is communicating with the extraembryonic coelom
HORIZONTAL FOLDING
Where would the somatic and splanchnic layers of lateral plate mesoderm be located in the inital stage of horizontal folding?
HORIZONTAL FOLDING
Where is the intraembryonic coelom?
HORIZONTAL FOLDING
What is the end result?
Formation of the Intraembryonic Coelom
(Midgut)
HORIZONTAL FOLDING
Technically, what is the intraembryonic coelom?
Space b/w the splanchnic and somatic portions of lateral plate mesoderm
HORIZONTAL FOLDING
What does the intraembryonic coelom communicate with?
Extraembryonic coelom
What is the splanchnopleura?
Splanchnic layer of the lateral plate mesoderm and the endoderm making up the yolk sack adjacent
What is the somatopleura?
Made up of somatic lateral plate mesoderm and ectoderm surrounding the amniotic cavity
Where is the splanchnic portion of the lateral plate mesoderm?
Adjacent to the yolk sac
Where does pinching off and formation of body cavities occur?
Where the umbillical cord IS NOT!!!
The sides come down and pinch off, forming the structures seen in the image
Label the diagram
Label the diagram
What is ectopia cordis?
Heart forms outside the body
What are the results of ectopia cordis?
- Heart formed outside body
- No pericardium
- Will be a bifed sternum
- Can result in death
Clinically, how can ectopia cordis be identified?
Ultrasound
The somatic layer of the lateral plate mesoderm is going to give rise to ___________________
The parietal part of any organ
The splanchnic layer gives rise to the _________ layer
Visceral
The pericardial cavity houses the:
Heart
The peritoneal cavity comprises:
The abdomen
Pericardial Cavity Formation
Describe
Lateral folds produce the heart!
Combination of endocardial primordia that initially has 2 segments, then merges cogether amongst the pericardial coelom
What is the
Somatic Layer?
Splanchnic Layer?
Somatic Layer = Parietal Pericardium
Splanchnic Layer = Visceral Pericardium
What innervates the diaphragm?
What nerve roots does it come from?
Phrenic nerves
C3, C4, C5
The pericardial cavity is separated from the pleural canals by _______________
Pleuropericardial Folds (Membrane)
The pleuropericardial folds come from ________ layer of the _______
SOMATIC; LATERAL PLATE MESODERM
Describe the development of lungs:
When the bronchial buds enter the pericardial peritoneal canals, they are immersed in the splanchnic layer lateral plate mesoderm.
Once those pleuralpericardial folds have separated everything, the pleural cavity for the lungs and mediastinum is formed.
Label the diagram
Look where the mouse cursor is:
What is this derived from?
Parietal pericardium is made from the somatic layer of lateral place mesoderm
What is the fibrous layer of the parietal pericardium made of?
Somatic layer of the lungs
Describe the formation of the diaphragm
The septum transversum requires pleuralperitoneal folds to meet the posterior body
Closure of the Pericardioperitoneal Canal
The pericardioperitoneal canal is closed by the approximation of the pleuroperitoneal folds with the septum transversum
The septum transversum gives rise to:
Central tendon
What are pleuroperitoneal membranes?
Overgrown by the muscle walls, don’t give rise to adult structures
Dorsal mesentary of the esophagus gies rise to:
The crura
The body wall give rise to:
Peripheral muscles
