Chapter 08 Body Cavities, Mesenteries, and Diaphragm

Chapter 08  Body Cavities, Mesenteries, and Diaphragm

Complete Chapter Questions And Answers
 

Sample Questions

5. ________ Large esophageal opening
A.
Costodiaphragmatic recess
B.
Cervical myotomes
C.
Congenital hiatal hernia
D.
Pleuroperitoneal membrane
E.
Pericardioperitoneal canal

ANS: C
If the embryonic esophageal hiatus or opening in the diaphragm is excessively large, abdominal viscera may herniate through it into the thorax, producing a congenital diaphragmatic hernia (CDH). Another uncommon type of CDH, the sliding hiatal hernia, is believed to be caused by a short esophagus. Because of this anomaly, the superior part of the stomach remains in the thorax and the stomach is constricted where it passes through the esophageal opening.

6. ________ Posterolateral diaphragmatic defect
A.
Costodiaphragmatic recess
B.
Cervical myotomes
C.
Congenital hiatal hernia
D.
Pleuroperitoneal membrane
E.
Pericardioperitoneal canal

ANS: D
If the pleuroperitoneal membrane fails to develop or to fuse with other parts of the diaphragm, a posterolateral defect develops, usually on the left side. Associated with this defect is herniation of abdominal viscera into the thorax and compression of the lungs. This type of CDH often results in a medical-surgical emergency because of difficulty in fetal breathing.

7. ________ Diaphragmatic muscles
A.
Costodiaphragmatic recess
B.
Cervical myotomes
C.
Congenital hiatal hernia
D.
Pleuroperitoneal membrane
E.
Pericardioperitoneal canal

ANS: B
The diaphragmatic muscles are mainly derived from myoblasts that migrate from the myotome regions of the cervical somites. Other myoblasts are derived from the myotome regions of the thoracic somites, and some myoblasts originate in the body wall tissues.

10. ________ Derived from the third to fifth cervical spinal cord segments
A.
Esophageal mesentery
B.
Pleuropericardial membrane
C.
Phrenic nerves
D.
Crura of the diaphragm
E.
Embryonic mediastinum

ANS: C
The phrenic nerves are derived from the third, fourth, and fifth cervical segments of the spinal cord. These nerves accompany the myoblasts that grow into the developing diaphragm from the myotome regions of the cervical somites. The diaphragm descends as elongation of the neck, descent of the heart, and expansion of the pericardial and pleural cavities occur. The descent of the diaphragm, after it receives its main nerve supply, explains the rather unusual course of the phrenic nerves.

11. ________ Muscular origins of the diaphragm
A.
Esophageal mesentery
B.
Pleuropericardial membrane
C.
Phrenic nerves
D.
Crura of the diaphragm
E.
Embryonic mediastinum

ANS: D
The crura of the diaphragm (muscular origins of diaphragm from superior lumbar vertebrae) develop as muscle fibers in the esophageal mesentery.