Development of the Diaphragm & Thoracic Viscera

Question 1

Answer 1

pleuroperitoneal hernia
pleural and peritoneal cavity communication where intestines are in the chest

Question 2

Answer 2

pericardioperitoneal hernia
failure of septum transversum and pleuropericardial folds to fuse near apex of heart resulting in intestines in pericardial sac

Question 3

Describe the steps that lead to partitioning of the embryonic coelom into the pericardial and pleural cavities

Answer 3

pleuropericardial folds separate the pleural cavities form the pericardial cavity

Question 4

Describe the steps that lead to partitioning of the embryonic coelom into peritoneal and pleural cavities

Answer 4

pleuroperitoneal folds separate peritoneal and pleural cavities in addition to the septum transversum

Question 5

Name the structures that contribute to the formation of the diaphragm and its hiatuses

Answer 5

2 pleuroperitoneal folds
septum transversum which is the primordium of the central tendons on diaphragm & is the ventral division between peritoneal cavity and pleural pericardial cavity

Question 6

Describe the processes that lead to the formation of the respiratory tree.

Answer 6

(trachea, bronchi, lungs begin as a diverticulum from caudal ventral pharynx lined with endoderm)
1. first appears as a laryngotracheal groove that expands into laryngotracheal diverticulum extending caudad ventral to esophagus
2. large opening between esophagus and trachea normally reduced by ingrowth of edges
3. lung buds becomes bronchial buds which become bronchia free

Question 7

tracheoesophageal fistula

Answer 7

failure of fusion/abnormal division of the opening between esophagus and trachea ; can be associated with esophageal atresia or stenosis

Question 8

esophageal atresia

Answer 8

no esophagus

Question 9

esophageal stenosis

Answer 9

narrowing of the esophagus

Question 10

what layer is the coelom formed from

Answer 10

lateral plate mesoderm

Question 11

what does the respiratory tree start as and how does it develop

Answer 11

starts as an outgrowth of the pharynx and opening is wide

it narrow/fuses with development

Question 12

four periods of lung development

Answer 12

1. pseudoglandular period
2. canalicular period
3. terminal sac/saccular period
4. alveolar perion

Question 13

describe the pseudoglandular period

Answer 13

lungs are glands
fetus cannot survive outside the uterus

Question 14

describe the canalicular period

Answer 14

vascularization, increased size/number of airways
if born near end, some may survive

Question 15

describe the terminal sac/saccular period

Answer 15

early development of respiratory surfaces, surfactant production
people/carnivores born late in this period “altricial young”

Question 16

describe the alveolar period

Answer 16

final development of alveoli, and well developed lungs
herbivores born during this period “precocial young”

Question 17

what lung development period can carnivores survive

Answer 17

terminal sac/saccular period