embryo- respiratory system Flashcards
during what week does the Laryngotracheal Groove & Lung Bud form?
week 4
Laryngotracheal groove appears in the __________
floor of caudal pharynx
how does the lung bud form?
Laryngotracheal Groove protrudes ventrally, forming an endodermal outgrowth from the foregut
the lung bud is also called the __________
respiratory diverticulum
what separates the lung bud (ventrally) from the foregut (dorsally)?
tracheoesophageal septum
The respiratory diverticulum retains a connection with the ______ at the primordial laryngeal inlet
pharynx
what condition can cause a risk of polyhydramnios?
Tracheoesophageal Fistula & Esophageal Atresia
an Esophageal atresia caused by what?
caused by posteriorly deviating septum
the lung bud becomes what?
Larynx, Trachea, Respiratory Tree, Lungs
the epithelial lining and glands of airways are from what germ layer of the lung bud?
endoderm
the _________ of the lung bud will give rise to smooth muscle and connective tissue of airways
splanchnic mesoderm
the _________ develops as the portion of the foregut immediately caudal to the pharynx
Esophagus
Laryngeal cartilages and musculature arise from which pharyngeal arch pairs?
pharyngeal arch pairs 4 and 6
Epiglottis forms from _________ of the caudal hypopharyngeal eminence
mesenchyme
Laryngeal mm. arising from 4th arch are innervated by which nerve?
superior laryngeal n.
Laryngeal mm. arising from 6th arch are innervated by the ___________ nerve
recurrent laryngeal n.
Lung bud divides to form two ______________
primary bronchial buds
the 2 primary bronchial buds will eventually become what?
primary bronchi
Primary Bronchial Buds Extend Into what?
Pericardioperitoneal Canals
the pericardioperitoneal canals eventually form what adult derivative?
pleural cavities
____________ gives rise to visceral pleura of the lungs
Splanchnic mesoderm
______________ lining thoracic body wall gives rise to the parietal pleura
Somatic mesoderm
Primary bronchial buds divide to form _________ buds
secondary (lobar) bronchial buds
Each secondary bronchus will supply what?
a lobe of the lung
a Tertiary bronchus and its surrounding tissue make up a ____________
bronchopulmonary segment
what are the 4 stages of lung development?
Pseudoglandular (6-16 weeks)
Canalicular (16-26 weeks)
Terminal sac (26 weeks to birth)
Alveolar (32 weeks to 8 years of age)
during the pseudoglandular phase, All major lung structures have developed except for what?
the most distal portions of respiratory tree where gas exchange occurs
during which stage of lung development does lung tissue becomes highly vascular?
canalicular stage
by the end of the canalicular stage, each terminal bronchiole has split into what?
2 respiratory bronchioles
during the terminal sac stage, what will develop?
More terminal sacs (primitive alveoli) develop. they are hugged by capillaries
the __________ barrier is formed during the terminal sac stage
blood-air barrier
during the terminal sac stage, Type II alveolar cells begin to do what?
produce, store, and secrete pulmonary surfactant
what is the job of pulmonary surfactant?
- Lines inner wall of alveolus
- reduces surface tension at the air-alveolar interface
- prevents alveolar collapse upon exhaling
when do Type II cells begin to produce surfactant?
weeks 20-22
Premature babies of 24 to 26 weeks may survive, but could suffer from _______________
Respiratory distress syndrome
what causes Respiratory distress syndrome?
lack of sufficient pulmonary surfactant production
what become fully functional during the alveoli stage?
Alveoli
95% of mature alveoli develop _________
postnatally
