Final Embryo - Respiratory Development Flashcards
This appears in the floor of the caudal pharynx
laryngotracheal groove
The laryngotracheal groove protrudes ventral forming an endodermal outgrowth from the foregut called what
lung bud (respiratory diverticulum)
This develops, separating the lung bud (ventrally) from the foregut (dorsally)
tracheosophageal septum
The respiratory diverticulum retains a connection with the pharynx where
primordial laryngeal inget
What abnormalities can occur during respiratory development and what risk is associated with them
tracheoesophageal fistula and esophageal atresia
risk of polyhydramnios
The lung bud develops to form what
larynx, trachea, respiratory tree, and lungs
This germ layer forms the epithelial lining and glands of the airway
endoderm
This germ layer forms the smooth muscle and CT of the airway
splanchnic mesoderm
This developed as the portion of the foregut immediately caudal to thy pharynx
esophagus
Which pharyngeal arch pairs give rise to the laryngeal cartilage and musculature
4 and 6
What forms the epiglottis
mesenchyme of the caudal hypopharyngeal eminence
Laryngeal muscules arising from the 4th arch are innervated by hat
superior laryngeal nerve
Laryngeal muscles arising from the 6th arch are innervated by what
recurrent laryngeal nerve
The lung bud divides to from what
the primary bronchial buds (future primary bronchi)
This type of mesoderm gives rise to the visceral pleura of the lungs
splanchnic mesoderm
This type of mesoderm lining the thoracic body gives rise to the parietal pleura
somatic mesoderm
The primary bronchial buds divide for form what
secodnary (lobar) bronchial buds
How many secondary (lobar) buds are there
3 on the right
2 on the left
The secondary bronchial buds divide to form what
teritiary (segmental) bronchial buds
What consists of a bronchopulmonary segment
tertiary bronchus + surrounding tissue
How many tertiary (segmental) buds are there
10 on the right
8 or 9 on the left
What stage of lung development happens during weeks 6- 16
pseudoglandular
What stage of lung development happens during weeks 16-26
canalicular
What stage of lung development happens from week 26 until birth
terminal sac
What stage of lung development happens from week 32 until 8 years of age
alveolar
In this stage of lung development all major lung structures have developed except for the most distal portions where gas exchange takes place
pseudoglandular stage
What does the lung tissue look like during the pseudoglandular stage
it appears histologically as a collection of exocrine glands
Can a fetus born during the pesudoglandular stage survive?
No
In this stage of lung development respiration is possible near the end where each terminal bronchiole has split into 2+ respiratory bronchioles developing primitive alveolar ducts
Canalicular stage
What becomes of the lung tissue during the canalicular stage
it becomes highly vascular
Can a fetus born during the canalicular stage survive?
At the end, possibly; although many die
In this stage of lung developments more terminal sacs develop and capillaries arrive firing the blood-air barrier; will see type I and type II alveolar cells
termninal sac stage
What is the purpose of type I alveolar cells
This is through which the gasses diffuse
What is the purpose of type II alveolar cells
they produce, store, and secrete pulmonary surfactant
This lines the inner walls of alveolus, reducing surface tension at the air-alveolar interface preventing alveolar collapse upon exhaling
pulmonary surfactant
When do type II alveolar cells begin producing surfactant
20-22 weeks, the amount though is insufficient for survival until weeks 26-28
What could a baby suffer from is born between 24-26 weeks due to insufficient surfactant
respiratory distress syndrom
In this stage of lung development, the alveoli are fully functional
alveolar stage
What percentage of mature alveoli develop postnatally continuing until 8 years of age
95% (most within the first three years)
