Body Cavities, Mesenteries and Diaphragm Development

Question 1

Where does the intraembryonic coelom develop?

Answer 1

Between the two layers of lateral plate mesoderm

Question 2

WHere are the itnraembryonic and extraembryonic contrinuous?

Answer 2

in the area of the yolk sac

Question 3

WHere will the pericarial, pleural and pericardial cavities be found in the intraembryonic coelom?

Answer 3

pericardial is at the cephalic curve or bend

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Question 4

What part of the lateral plate mesoderm forms the parietal and visceral layers, respectively, of the serous cavities?

Answer 4

the somatic mesoderm forms the parietal layer

the splanchnic mesoderm forms the visceral layer

Question 5

What developmental malformation do ectopia cordis, congenital umbilical hernia, gastroschisis and estrophy of the bladder have in common?

Answer 5

They are all the result of impaired lateral folding in the horizontal plane

Question 6

How does the primitive pericardial cavity reach the cardiac region of the thorax

Answer 6

through cephalocaudal folding

Question 7

What are the pericardioperitoneal canals?

Answer 7

They are open spaces that connect the developing pericardial, pleural and peritoneal cavities - located on each side of the foregut

Question 8

What is the function of the dorsal mesentery?

Answer 8

the foregut, midgut and hindgut are suspended form the posterior abdominal wall by dorsal mesentery, which also serves to carry blood vessels and nerves to visceral organs

Question 9

What is the purpose of the pleuropericardial membranes?

Answer 9

They divide the thoracic cavity into a pericardial cavity and two pleural cavities by fusing with each other at the root of the lungs

Question 10

What adult structure do the pleuropericardial membranes form?

Answer 10

forms the fibrous pericardium (and surface cells form the parietal serous pericardium)

also contain the common cardinal veins and phrenic nerves

Question 11

What is the purpose of the pleuroperitoneal membranes?

Answer 11

they fuse with the dorsal mesentery fo the esophagus and transverse septum to separate the pleural cavities from the peritoneal cavity - closing the pericardioperitoneal canal

Question 12

What are the four developmental components that contribute to the diaphragm?

Answer 12

1. transverse septum (central tendon and ventral mesentery_
2. pleuroperitoneal membranes (form the lubocostal trigone)
3. Dorsal mesentery of the esophagus (form the right and left crurua of the diaphragm)
4. Lateral and dorsal body walls - myoblasts grow in an dform the costal portion of the diaphragm

Question 13

What cervical nerves innervate the major muscle mass of the diaphragm?

Answer 13

phrenic nerve with fibers from cervical nerves 3, 4, and 5

Question 14

What nerves contribute to the sensory innervation of the diaphragm?

Answer 14

the phrenic neres supplies all of the diaphragm except the costal margins which develop from lateral body wall and therefore receive sensory innervation from the lower intercostal nerves.

Question 15

Why is the phrenic nerve associated with the fibrous pericardium of the adult?

Answer 15

Because the phrnic nerve fibers fold down with the pleuropericardial folds, which eventually forms the fibrous pericardium

Question 16

What fails to occur when a congenital diaphragmatic hernia develops?

Answer 16

failure of pleuroperitoneal folds to fuse, resulting in a defect in the diaphragm at the lumbocostal trigone

Question 17

Why may polyhydramnios be present with this malformation?

Answer 17

excess amniotic fluid is present because the GI tract is up in the thoracic cage and the lungs and heart can’t develop properly. Somehow this means that less of the amniotic fluid gets absorbed to the lungs and less gets pumped back to mom in baby’s waste. This leaves more amniotic fluid in the amniotic sac.

Question 18

Why does herniation of abdominal viscera usually occur on the left side?

Answer 18

the left pericardioperiteonal canal is larger than the right and closes later. so usually the left lung is hypoplastic and the heart is displaced to the right

Question 19

What happens to the thoracic viscera?

Answer 19

1

Question 20

What is the difference betwen a congential diaphragmatic hernia and eventration of the diaphragm?

Answer 20

with congential diaphragmatic hernia, the lumbocostal trigone doesn’t fuse so you have an actual hole.

with eventration the diaphragm forms but doesn’t have enough muscle mass, so it gets pushed up into the thoracic cavity

Question 21

Where do congenital esophageal hiatal and retrosternal hernias occur?

Answer 21

esophageal hiatal - stomach gets pushed up into the chest wall through the opening in the diaphragm for the esophagus - the hiatus

retrosternal - gut herniates between the sternum and the diaphragm

Question 22

Which of the following is not derived from splanchnic layer of the lateral plate mesoderm?
A. CT fo the lungs
B. GLands of the stomach
C. Smooth muscle of the stomach
D. Visceral pleura

Answer 22

B glands of the stomach

Question 23

Which of the following adult structures is derived from the pericardioperitoneal canal?
A. Diaphragm
B. Pericardial sac
C. Peritoneal cavity
D. Pleural cavity

Answer 23

D pleural cavity

Question 24

What part of the lateral plate mesoderm is responsible for forming the body wall?
A. Splanchnic layer
B. Somatic layer

Answer 24

B. Somatic layer

Question 25

What name is used to refer to herniation of abdominal organs occurring between the umbilicus and the pubic bone?
A. epigastric hernia
B. hypogastric hernia
C. Umbilical hernia

Answer 25

B hypogastric hernia

Question 26

Which of the following is derived from dorsal mesentery?
A. Falciform ligament
B. Hepatoduodenal ligemtn
C. hepatogastric ligament
D. lesser omentum
E. mesentery proper

Answer 26

E. mesentery proper

Question 27

During development, which of the following structures separates the pericardial region of the itnraembryonic coelom from the developing pleural cavity.
A. Dorsal mesocardium
B. Falciform ligament
C. Pleuropericardial membrane
D. Pleuroperitoneal membrane
E. Transverse septum

Answer 27

C. pleuropericardial membrane

Question 28

During development, which of the following structures contains the caval veins and the phrenic nerve?
A. Dorsal mesocardium
B. Falciform ligament
C. Pleuropericardial membrane
D. Pleuroperitoneal membrane
E. Transverse septum

Answer 28

C. Pleuropericardial membrane

Question 29

Which structure gives rise to the fibrous pericardium
A. Dorsal mesocardium
B. Falciform ligament
C. Pleuropericardial membrane
D. Pleuroperitoneal membrane
E. Transverse septum

Answer 29

C. Pleuropericardial membrane

Question 30

Which of the following structures gives rise to the central tendon of the diaphragm?
A. Dorsal mesentery
B. Lateral and dorsal body walls
C. Pleuropericardial membrane
D. Pleuroperitoneal membrane
E .Transverse septum

Answer 30

E. Transverse septum

Question 31

The lumbocostal triangle of the diaphragm is derived from the :
A. Dorsal mesentery
B. Lateral and dorsal body walls
C. Pleuropericardial membrane
D. Pleuroperitoneal membrane
E .Transverse septum

Answer 31

D. pleuroperitoneal membrane

Question 32

Myoblasts migrating into the transverse septum are derived from:
A. cervical myotomes 3, 4, and 5
B. costal myostomes 10, 11, and 12
C. lumbocostal triangle
D. pleuropericardial membrane
E. thoracic myotomes 1-4

Answer 32

A. cervical myotomes 3, 4, and 5

Question 33

Which of the following fails to develop completely when a newborn has a diaphragmatic hernia?
A. Diaphragmatic pleura
B. fibrous pericardium
C. intercostal membrane
D. lumbocostal triangle
E. pleuropericardial membrane

Answer 33

D. lumbocostal triangle