Respiratory System Flashcards
What does the distal end of the laryngotracheal diverticulum enlarge to become?
respiratory bud
What does the laryngotracheal groove elongate ventrally to the developing foregut to become?
laryngotracheal diverticulum
When longitudinal tracheoesophageaal folds folds fuse, what do they form?
tracheoesophageal septum
what forms ventrally of the tracheoesophageal septum?
laryngotracheal tube
What does the laryngotracheal tube give rise to?
larynx, trachea, bronchi, and lungs
The communication between the laryngotracheal tube and the pharynx is restricted to what?
primordial laryngeal inlet
Where is the larynx epithelium derived from?
endoderm of laryngotracheal tube
After rapid proliferation and temporary occlusion of laryngeal lumen, what remains after the lumen recanalizes?
vocal fold and vestibular fold
What happens if thee lumen doesnt fully recanalize?
atresia (complete blockage) or stenosis (narrowing) of lumen
Where is the epiglottis derived from?
hypopharyngeal eminence (arches 3&4)
Where are larynx cartilages and mm derived from?
arches 4&6 (CNX innervation)
What gives rise to the epithelium and glands of the trachea?
endoderm of laryngotracheal tube
The splanchnic mesoderm gives rise to what in terms of the trachea?
cartilage, CT and mm
What is a tracheoesophageal fistula?
abnormal persistent connection between trachea and esophagus
due to defective tracheoesophageal septum
From what do primary bronchial buds grow from?
respiratory bud on medial wall toward developing pleural cavity
Where do pleuropericardial folds form?
on lateral wall of pleural cavity superior to bronchial buds
What fuses medially with the septum transversum?
pleuropericardial folds
Pleuropericardial folds contribute to the formation of what?
mediastinum
Where do pleuroperitoneal folds form?
form on lateral wall of pleural cavity inferior to bronchial buds
What fuses transversely with septum transversum?
pleuroperitoneal folds
What does the pleuroperitoneal folds form?
thoracic diaphragm
On R side, the secondary buds will supply what?
upper = upper lobes lower = middle and lower lobes
What do segmental bronchi supply?
bronchopulmonary segments
Respiratory bronchioles are present when what have formed?
17 orders of dichotomous branches
How many dichotomous branches will form after birth?
7
Where doe the thoracic diaphragm form initially?
opposite cervical somites 3-5
Myoblasts draw innervation from cervical somites 3-5 to cause what kind of innervation to the thoracic diaphragm?
phrenic nerve innervation
Where does the thoracic diaphragm move as embryo grows?
caudally
What is the pseudoglandular stage of lung maturation
bronchial tree has formed but NO alveoli present!
NO respiration
What is the Canalicular stage?
upper parts of the resp system develop prior to lower parts
bronchial tree lumen is enlarging
tissue becoming highly vascular
resp bronchioles with 3-6 alveolar ducts and some alveolar sacs present = respiration possible!
What is the terminal sac stage?
many alveolar sacs form
- type I pneumocytes line rudimentary alveoli
- type II pneumocytes produce surfactant
capillaries invade interalveolar septa
respiration possible
What is the alveolar stage?
type I pneumocytes thin
interalveolar capillaries bulge into alveolar lumen
lungs well developed
mature alveoli develop after birth
Why is fetal breathing important?
- causes aspiration of amniotic fluid in lungs = absorption and turnover of amniotic fluid through placental exchange
- mvmt essential for normal lung development
At birth fluid is removed by what three mechanisms?
1) through mouth/nose in response to thoracic pressure
2) absorption into pulmonary vasculature
3) absorption into pulmonary lymph
Initial breathing is likely due to what?
- decrease in O2 and Increase in CO2
- cutaneous stim
- cold air stim
When is rhythmic breathing established? how many breaths/min?
about 1 minute and 40 breaths/min
What is oligohydraminos?
insufficient amount of amniotic fluid
- retarded lung development and compromised fetal breathing mvmts
What is respiratory distress?
insufficient surfactant levels => labored breathing
What is agenesis of the lung?
failure of development of resp bud
- unilateral = compatible with life - bilateral = incompatible
What is lung hypoplasia?
reduced lung volume and hypertrophic smooth mm in pulmonary aa.
- pulmonary hypertension - pulmonary blood flow compromised
