Body Cavities, Mesenteries, and Diaphragm Development

Question 1

Intraembryonic coelom develops in the

Answer 1

lateral plate mesoderm and the cardiogenic (heart-forming) mesoderm

Question 2

The intraembryonic coelom gives rise to the

Answer 2

pericardial, pleural and peritoneal cavities.

Question 3

The pericardioperitoneal canal connects the

Answer 3

pericardial and peritoneal cavities and later in development is the area where the pleural cavities are formed.

Question 4

Cephalo-caudal folding carries the heart and pericardial cavity

Answer 4

ventro-caudal to the developing foregut

Question 5

The lateral folding

Answer 5

forms the walls of the trunk

carries the somatic mesoderm of the lateral plate ventrally to form the walls of the thoracic and abdominal regions.

Question 6

Ectopia cordis with cleft sternum: What is it

Answer 6

• a failure in lateral folding

- heart outside of the thoracic cavity

Question 7

Congenital umbilical hernia: what is it

Answer 7

• a failure in lateral folding
• defect in the muscle and connective tissue of the anterior abdominal wall resulting in the protrusion of intestine and greater omentum through the defect
• skin and superficial fascia (subcutaneous tissue) cover protruding mass usually located above (epigastric) or below (hypogastric) the umbilicus

Question 8

Extrophy of the bladder: what is it

Answer 8

Urinary bladder opens onto the anterior body wall

Failure of lateral folding leads to a defect in the ventral body wall in the hypogastric region, and the interior of the urinary bladder is exposed. Why the anterior wall of the urinary bladder is exposed is not known, but may be due to some growth factor affecting the developing urinary bladder.

Question 9

Heart development occurs _____ to the developing brain

Answer 9

rostral to the developing brain

Question 10

Dorsal mesentery does what

Answer 10

suspends foregut, midgut and hindgut from the posterior abdominal wall; carries blood vessels and nerves

Question 11

Pleuropericardial folds (membrane) divides the

Answer 11

thoracic cavity into a pericardial cavity and two pleural cavities

Question 12

Pleuropericardial folds contains the

Answer 12

common cardinal vein and the phrenic nerves

Question 13

Pleuropericardial folds forms the

Answer 13

fibrous pericardium; surface cells form the serous membranes (parietal pericardium and mediastinal pleura)

Question 14

Pleuroperitoneal folds (membrane) serve to close the

Answer 14

caudal end of the pericardioperitoneal canal.

Grow ventrally to fuse with the dorsal mesentery of the esophagus and the transverse septum, thereby separating the pleural cavities from the peritoneal cavity.

Question 15

Cephalic-caudal folding brings the transverse septum

Answer 15

into the thorax

Question 16

the transverse septum: becomes the

Answer 16

central tendon of the diaphragm and the ventral mesentery of the foregut

Question 17

Pleuroperitoneal folds (membranes):

Answer 17

close the pericardioperitoneal canal and form the vertebrocostal or lumbocostal trigone

Question 18

Dorsal mesentery of the esophagus

Answer 18

• form the right and left crura of the diaphragm

Question 19

Myoblasts from the myotome region of cervical somites 3,4 and 5 migrate into

Answer 19

mesenchyme of transverse septum

carry with them innervation from cervical nerves 3,4 and 5, becomes phrenic nerve

Question 20

Myoblasts in the transverse septum migrate into the other components of the

Answer 20

diaphragm, carrying motor branches of the phrenic nerve

Question 21

Sensory fibers of the phrenic nerve supply all of the

Answer 21

diaphragm, except the costal margin, which receives sensory innervation from lower intercostal nerves
referred pain

Question 22

Congenital diaphragmatic hernia

Answer 22

Due to defective development or failure of the pleuroperitoneal membranes to fuse with other diaphragmatic components; resulting in a posterolateral defect in the diaphragm (vertebrocostal or lumbocostal trigone)

Herniation of abdominal contents into thoracic cavity occurs

Polyhydramnios (excess amniotic fluid) may be present

Defect is usually unilateral and on the left side because left pericardioperitoneal canal is larger than the right and closes later; left lung hypoplastic, and heart and mediastinum displaced to the right

Question 23

Congenital esophageal hiatal hernia

Answer 23

Herniation of stomach through the esophageal hiatus

Thought to be due to failure of the esophagus to elongate sufficiently as the neck and thorax develop

Congenitally enlarged esophageal hiatus may be the predisposing factor to adult hiatal hernia

Question 24

Lateral plate mesoderm Splanchnic component forms the

Answer 24

visceral layer of the serous membranes covering the lungs, heart and abdominal organs (also connective tissue and smooth muscle)

Question 25

somatic component of the lateral plate mesoderm forms the

Answer 25

parietal layer of the serous cavities

Question 26

What part of the lateral plate mesoderm is responsible for forming the body wall?

Answer 26

Somatic layer

Question 27

What name is used to refer to herniation of abdominal organs occurring between the umbilicus and the pubic bone?

Answer 27

Hypogastric hernia.

Question 28

Mesentery proper is formed from the

Answer 28

dorsal mesentery

Question 29

During development, which of the following structures separates the pericardial region of the intraembryonic coelom from the developing pleural cavity?

Answer 29

Pleuropericardial membrane

Question 30

During development, which of the following structures contains the caval veins and the phrenic nerve?

Answer 30

Pleuropericardial membrane

Question 31

What structure gives rise to the fibrous pericardium?

Answer 31

Pleuropericardial membrane

Question 32

Retrosternal (parasternal) hernia

Answer 32

• gut herniation between sternum/ribs and the diaphragm

- greater omentum or gut may be present in the pericardial cavity

Question 33

Which of the following structures gives rise to the central tendon of the diaphragm?

Answer 33

Transverse septum

Question 34

The lumbocostal triangle of the diaphragm is derived from the:

Answer 34

pleuroperitoneal membrane.

Question 35

Myoblasts migrating into the transverse septum are derived from:

Answer 35

cervical myotomes 3, 4 and 5.

Question 36

Which of the following fails to develop completely when a newborn has a diaphragmatic hernia?

Answer 36

Lumbocostal triangle