Embryo (04.15) Development of Respiratory System Flashcards
the laryngotracheal groove and lung development occur during what week
4
the laryngotracheal groove appears in the FLOOR of the ____ ____
caudal pharnyx
the laryngotracheal groove protrudes ventrally forming an endodermal outgrowth from the foregut known as the ___ ___
lung bud (respiratory diverticulum)(laryngotracheal diverticulum)
the tracheoesophageal septum develops and separates the ____ ___ (ventrally) from the ____ (dorsally)
- lung bud
- foregut
the respiratory diverticulum retains a connection with the pharynx at the ___ ___ ___
primordial laryngeal inlet
esophageal atresia is caused by what
POSTERIORLY deviating septum
abnormal connection of the esophagus joining on the inferior side of the trachea (septum does not fully form)
tracheoesophageal fistula (TEF)
too much amniotic fluid present
polyhydramnios
concerning lung bud derivatives, the endoderm gives rise to what two things?
- epithelial lining
- glands of airways
concerning the lung bud derivatives, the splanchnic mesoderm gives rise to what two things?
- smooth m
- CT of airways
concerning the lung bud derivatives, the splanchnic mesoderm gives rise to what two things?
- smooth m
- CT of airways
the esophagus develops as the portion of the ____ immediately caudal to the _____
- foregut
- pharynx
LARYNGEAL CARTILAGES and MUSCULATURE arise from pharyngeal arch pairs ____ and ___
- 4
- 6
the EPIGLOTTIS forms from _____ of the caudal ______ eminence
- mesenchyme
- hypopharyngeal
laryngeal mm arising from the 4th arch are innervated by what?
superior laryngeal n
laryngeal mm arising form the 6th arch are innervated by what?
recurrent laryngeal n
the lung bud divides to form two ____ ____ ___ (future primary bronchi)
primary bronchial buds
what day does the lung bud divide?
28
the primary bronchial buds extend into ____ ____
pericardioperitoneal canals
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_____ ____ gives rise to visceral pleura of the lungs
splanchnic mesoderm
___ ____ lining thoracic body wall gives rise to the parietal pleura
somatic mesoderm
___ ___ becomes the pleural cavity
pericardioperitoneal canal
___ ___ becomes the pleural cavity
pericardioperitoneal canal
primary bonchial buds divide to form ____ ___ ___
secondary (lobar) bronchial buds
each secondary bud will supply ___ ___ of the lung
one lobe
concerning secondary buds, there are ___ on the right and ___ on the left
- 3
- 2
on what day do the primary buds divide into secondary
30
secondary bronchial buds divide to form ____ ___ ___
tertiary (segmental) bronchial buds
what composes a bronchopulmonary segemnt
- tertiary bronchus
- surrounding tissue
concerning tertiary buds, there are ___ on the right and ____ on the left
- 10
- 8-9
what is the pathway of airflow?
- trachea
- primary bronchi
- secondary (lobar)
- tertiary (segmental)
- bronchioles
- terminal bronchioles
- respiratory bronchioles
- alveolar ducts
- terminal sacs
- alveoli
what is the main site of gas exchange
alveoli
what are the four stages of lung development
- pseudoglandular (6-16 weeks)
- canalicular (16-26 weeks)
- terminal sac (26 weeks - birth)
- alveolar (32weeks- 8 years)
pseudo glandular stage is where all major lung structures have developed except for the most distal portions of the ____ ___ where ___ ___ occurs
- respiratory tree
- gas exchange
will a fetus that is born during the psedoglandular stage survive?
no
will a fetus that is born during the psedoglandular stage survive?
no
during the terminal sac stage, terminal sacs develop and are hugged by _____, establishing the ___-___ ____
- capillaries
- blood-air barrier
at the END of the canalicular stage, what is possible
respiration
during the canalicular stage, each terminal bronchiole has split into 2(+) ___ ____, which have developed primitive ___ ____. some of these ducts already lead into ___ ___
- respiratory bronchioles
- alveolar ducts
- terminal sacs
can a fetus survive if it is born in the canalicular stage?
yes if it is at the end (although many will still die)
can a fetus survive if it is born in the canalicular stage?
yes if it is at the end (although many will still die)
slide
20
at what wee do terminal sac walls = a single layer of simple squamous cells?
26
most of the terminal sac simple squamous cells are ____ ____ ____ ____ through which gases diffuse
type I alveolar cells
scattered amongst the type I cells are a few rounded TYPE II ALVEOLAR CELLS that produce, store, and secrete ____ ___
pulmonary surfactant
lines inner wall of alveolus, reduces surface tensions at the air-alveolar interface, and prevents alveolar collapse upon exhaling
pulmonary surfactant
type II cells begin to produce surfactant at ___-___ weeks but the amount of surfactant is insufficient for survival of premature infants until about weeks ___-___
- 20-22
- 26-28
premature babies of 24-26 weeks may survive, but could suffer from ___ ___ ___ do to insufficient surfactant
respiratory distress syndrome
when is there fluid filled alveoli and the pulmonary surfactant stored in type II alveolar cells
before birth
when does the secreted surfactant form layers on top of the remaining fluid
first inhale
when is the first time that the surfactant prevents alveolar collapse
first exhale
at what stage are the alveoli fully funcitonal
alveolar stage (32 weeks- 8 years)
95% of mature alveoli develop _____ and will continue to develop until ___ years of age
- postnatally (most form within first 3 years)
- 8
