Development of Body Cavities (Exam 2) Flashcards
What layer of the embryo is closest to the notochord?
Mesoderm
What will lateral plate mesoderm split into by the end of the 3rd week
Splanchnic (visceral) and Somatic mesoderm (parietal)
What does intermediate mesoderm give rise to
urogenital system
What does paraxial mesoderm give rise to
musculoskeletal system
What other layer of the embryo is the splanchnic mesoderm associated with
underlying endoderm
What is somatopleure
association between the somatic mesoderm and the ectoderm
What is a splanchnopleure
association between the splanchnic mesoderm and the endoderm
Where does the intraembryonic coelom develop
between the somatopleure and splanchnopleure
What type of tissue will line the yolk sac
endoderm
What body cavity changes will be seen after lateral folding
yolk sac incorporated
primitive body cavity forms
formation of dorsal mesentery
What is the incorporated yolk sac known as
primitive gut tube
What is the primitive body cavity initially continuous with
chorionic cavity (extraembryonic coelom)
What composes the dorsal mesentery
parietal and visceral mesoderm
What is a mesentery
double-layered fold of peritoneum
What is the function of a mesentery
provide pathway for blood vessels, nerves, and lymphatics
allow organ movement
What type of peritoneum lines the body wall
parietal peritoneum
What type of peritoneum lines the viscera
visceral peritoneum
What is the vitelline duct
connects yolk sac to the primitive gut tube (midgut lumen)
What are the two types of embryonic folding
longitudinal (had to tail)
transverse-lateral folding
What does longitudinal head to tail folding result in
cariogenic area is shifted into the thorax
yolk sac is incorporated
What does transverse-lateral folding result in
incorporation of yolk sac
body cavity formation
How is the intra-embryonic coelom formed and divided
differential growth coupled with folding
What is the inside of the body cavity lined by
mesodermal derivatives
How are the different parts of the lateral plate mesoderm innervated
somatic: GSA
Splanchnic: GVA
What is the intraembryonic coelom originally continuous with
chorionic cavity
What will the intraembryonic coelom form within the thorax
pericardial cavity
What will the intraembryonic coelom form within the abdomen/pelvis
peritoneal cavity
What will the intraembryonic coelom form within the pericardioperitoneal cavities
pleural cavities
What does the coelomic epithelium give rise to
smooth muscle and CT of tubes (mesoderm), cardiac muscle, sustentacular cells, epithelium of reproductive
What is ectopiacordis
heart is outside the chest wall
What causes ectopiacordis
ventral wall defect, failure of somatic mesoderm to fuse properly
What is gastrochisis
abdominal organs develop outside of the body wall
Where is the defect in gastrochisis usually found
to the right of the umbilical cord
What causes gastrochisis
somatic mesoderm failing to form properly
What covers the organs in gastrochisis and what is clinical correlation because of this
only visceral peritoneum and therefore exposed to amnion, corrosive
What are the risks of gastrochisis
organs exposed to amniotic fluid which is corrosive
vulvus
What is vulvus
organs twist around themselves and lose blood supply
What are the different types of ventral wall defects
cleft sternum
ectopia cordis
omphalocele
What is omphalocele
failure of guts to return after physiological herniation
What are the 3 cavities that the intraembryonic cavity is continuous through
pleural cavities
pericardial cavity
peritoneal cavity
What is the septum transversum
thickened mass of lateral plate of mesoderm
Where is the septum transversum situated
cranial end of embryo between heart and liver
What does the septum transversum seperate
intraembryonic coelom into thoracic and abdominal cavities
The septum transversum is initially what
INCOMPLETE
What will the septum transversum ultimately become
part of the diaphragm
What are pericardioperitoneal canals
canals on either side of the septum transversum that maintain continuity between 3 body cavities
Where do developing lungs expand, and what does this result in
expand into pericardioperitoneal cans
expansion forms ventral body wall and pleuropericardial folds
What does rapid growth of the lung buds split body wall mesoderm into
definitive body wall
pleuropericardial membranes
What do pleuropericardial membranes contain
common cardinal veins and phrenic nerves
As the lung buds grow, where do the pleuropericardial membranes project
medially
What do the pleuropericardial folds separate
pericardial cavity from the pleural cavity
What do the pleuropericardial folds give rise to
fibrous pericardium and parietal serous pericardium
mediastinal pleura
What will the pleuropericardial membranes enclose once they fuse
two pleural cavities and one pericardial cavity
What will provide innervation to the pericardium and parietal pleura
phrenic nerve
What 4 structures is the diaphragm derived from
septum transversum
mesoderm
pleuroperitoneal folds
dorsal mesentery
What supplies muscle to the diaphragm
paraxial mesoderm
What will form the central tendon of the diaphragm
septum transversum
What will the pleuroperitoneal membranes contribute to the diaphragm
lateral edges of central tendon
What will the esophageal mesentery contribute to the diaphragm
right and left crura
What will the paraxial mesoderm contribute to the diaphragm
most muscle of the diaphragm
What is congenital diaphragmatic hernia
intestines herniate into pleural cavity
What is the most common congenital herniation
hernia of Bochdalk
What is hernia of Bochdalek
congenital diaphragmatic hernia
What causes congenital diaphragmatic hernia
failure of peritoneal membrane to fuse and close the pericardioperitoneal canal
What side do congenital diaphragmatic hernias usually occur on and why
left
left is larger and closes at a later time
What is defective in an esophageal hernia (hiatal hernia)
defect in right crus or short esophagus
What occurs is an esophageal hernia
stomach is constricted at level of diaphragm and herniates into thorax
What is defective in parasternal hernia
deficit between the sternal and costal heads of the diaphragm
What is diaphragm innervated by
phrenic nerve
Where will dorsal and ventral mesentery be seen
dorsal mesentery suspends gut tube from posterior body wall
ventral mesentery only develops in the foregut region (diaphragm to yolk stalk)
Where is the ventral mesentery derived from
septum transversum
How will blood vessels supplying the gut travel
through mesentery
What are the arteries associated with dorsal mesentery
celiac trunk
superior mesenteric
inferior mesenteric
What region does the celiac trunk supply
foregut
What region does the superior mesenteric supply
midgut
What region does the inferior mesenteric supply
hindgut
What are the derivatives of dorsal mesentery
greater omentum mesoesophagus transverse mesocolon mesoappedix sigmoid mesocolon mesentery proper gastrophenic ligament gastrosplenic ligament gastrocolic ligament phrenicolienal ligament phrenicolic ligament
What are the derivatives of ventral mesentery
lesser omentum hepatogastric fold hepatoduodenal lig coronary lig falciform lig triangular ligaments
Where does the spleen develop from
mesoderm
What layer is the spleen developed in
dorsal mesentery
What are ligaments associated with the spleen
lienorenal
gastrosplenic
What does the lienorenal ligament do
connect spleen to body wall
What does the gastrosplenic ligament do
connect spleen to stomach
How is the spleen classified
intraperitoneal
What does it mean if an organ is intraperitoneal
completely surrounded by mesentery
What are examples of intraperitoneal organs
stomach transverse colon sigmoid colon spleen jejunum/ileum duodenum part 1 and distal part 4
What are the two types of retroperitoneal
primary and secondary
What is a retroperitoneal organ classified as
organ not completely surrounded by mesentery
What are primary retroperitoneal organs
organs that never had a mesentery
What are examples of primary retroperitoneal organs
aorta, IVC
kidneys, bladder, ureters
What is a secondary retroperitoneal organ
had a mesentery but lost it partially in development
What are examples of secondary retroperitoneal organs
duodenum part 2-proximal 4 ascending and descending colon rectum pancreas liver, gallbladder
How does the mental bursa form
right side of the dorsal mesentery thins and the stomach rotates to the left
pulls dorsal mesentery from the posterior wall.
What is the epiploic foramen of Winslow
connection between omental bursa and greater sac
