Diaphragm Problems & Embryology

Question 1

Congenital Diaphragmatic Hernia

Answer 1

Failure of the pleuroperitoneal folds to fuse or develop –> herniation of abdominal contents into the pleural cavity

Usually on the left posterolateral side.

Associated with pulmonary hypoplasia (incomplete lung development bc herniation compresses lung)

Question 2

Septomarginal trabecula (moderator band)

Answer 2

Forms a bridge between the IV septum and the base of the anterior papillary muscle

It prevents over distention of the ventricle and carries the Purkinje fibers of the AV bundle from the septum to the ventricle wall.

Question 3

Eventration of the diaphragm

Answer 3

Myoblasts in the body wall fail to form one of the muscular hemidiaphragms

–> abdominal organs pushed into thorax & paradoxical respiration

Question 4

What structure fails to develop in tracheoesophageal fistula?

Answer 4

Tracheoesophageal septum, which separates the foregut (esophagus) from the laryngotracheal tube; can cause aspiration pneumonia aspiration pneumonia

Question 5

Esophageal atresia

Answer 5

Tracheoesophageal septum deviates too far dorsally –> Blind-ending esophagus allows air into the stomach.

Cyanosis & laryngospasm
EA with TEF is associated with other anomalies: VACTREL (Vertebral defects, Anal atresia, Cardio defects, TEF, Renal defects, Limb defects)

Question 6

_______ form the posterolateral part of the diaphragm.

_______ form the fibrous pericardium & separates the pericardial cavity from the pleura cavity.

Answer 6

Pleuroperitoneal folds form the posterolateral part of diaphragm

Pleuropericardial folds separate the pericardial cavity form the plerual cavity and form the fibrous pericardium;

Question 7

Webs and strictures around the distal third of the esophagus indicate what?

Answer 7

Esophageal stenosis, results from failure of esophageal recanalization in the 8th wk or from remnants of tracheal cartilaginous rings or from hypertrophy

Question 8

Morgagni hernia

Answer 8

Defect in the pleuroperitoneal membrane just lateral to the xiphoid process.

Sharp, epigastric pain

Question 9

Pulmonary Agenesis

Answer 9

Failure of bronchial buds to develop –> absent lung, lobe or a lobe w/ bronchi

Question 10

Pulmonary hypoplasia

Answer 10

Poorly developed bronchial tree

Question 11

Deficiency of absence of surfactant –> alveoli collapse

Premature infants, infants of diabetic mothers, multiple birth infants, and infants who had fetal asphyxia or maternofetal hermorrhage.

Dyspnea, tachypnea, inspiratory retractions of chest wall, cyanosis, nasal flaring. Ground-glass appearance in both lungs.

Betamethasone (corticosteroids) increase surfactant production

Answer 11

Respiratory Distress Syndrome

Question 12

Aspiration pneumonia is associated with ___, but not ___.

Answer 12

Associated with tracheoesophageal fistuala, but esophageal atresia.

Question 13

What embryological structure gives rise to the esophagus?

Answer 13

Foregut

Question 14

What 3 cavities (coelom) form in the 4th week of development?

How do these become the 3 P’s (pleural, pericardial, and peritoneal) cavities?

Answer 14

Thoracic cavity
Peritoneal cavity
Pericardioperitoneal canals (lateral to esophagus, allows communication between the two above cavities)

Head fold pulls the cardinal veins and its associated pleuropericardial folds toward the midline, where they fuse with the dorsal mesentery to form the pericardial and pleural cavities.

Question 15

Wings of the diaphragm come from

Answer 15

Pleuropericardial folds

Question 16

The myoblasts that form the diaphragmatic muscle start out on the ____, ride down, and spread out on the wings of the diaphragm.

Answer 16

Septum transversum

Question 17

Tracheobronchial diverticulum

Answer 17

Primitive pharynx that grows out of the foregut; holds the endoderm-lined Laryngotracheal groove: forms the epithelium and glands of larynx.

Question 18

What does the primitive larynx look like?

Answer 18

Mesoderm (becomes cartilage and muscle) covering endoderm (internal lining of epithelium for bronchial tree)

Question 19

Whenever you see branching, Epithelial-to-mesenchymal transition is occurring.

Answer 19

Wnt/B-Catenin signaling is critical to this

Question 20

VACTREL (associated with EA+TEF)

Answer 20

Vertebral defect
Anal atresia
Cardiac anomalies
Tracheoesphageal fistula
Renal anomalies
Esophageal atresia
Limb deformities

Question 21

4 stages of lung development

Answer 21

Pseudoglandular (wk5-17): terminal sacs formed, but no exchange.

Canalicular phase (ends wk25): respiratory bronchioles and alveolar ducts formed, no exchange.

Terminal sac period (ends @birth): development of type I and II alveolar epithelial cells finally allow for gas exchange

Alveolar period (ends childhood): well-developed

Question 22

Congenital lung cysts are due to

Answer 22

Dilation of terminal bronchi