Lung Development Flashcards
What is laryngotracheal groove and where does it develop?
It turns into larynx and trachea (duh, name) and is from ventral wall of primitive pharynx caudally to the 4th pair of pharyngeal pouches.
What are the lung and its glands derived from?
Endoderm, from GI outgrowths.
What is surrounding tissue of the lung derived from?
Splanchnic mesenchyme (splanchnic means organ, so it is synonomous with visceral, just that greek vs latin bull shit)
What part of the resp system comes from neural crest mesenchyme?
Laryngeal cartilage
What separates the respiratory diverticulum (will develop into pathway for air) form the developing foregut?
Tracheoesophageal fold which will eventuall form a tacheoesophageal septum which eventually causes separation of esophagus form developing resp system
Where is epithelial lining for the larynx from?
Endoderm (from the foregut, makes sense, next to GI system)
Where are laryngeal cartilages derived from?
4th and 6th pharyngeal arches from neural crest mesenchyme
What innervates larynx?
VAGUS NERVE (that innervates things from the 4th and 6th pharyngeal arches). recurrent laryngeal is motor, superior laryngeal is sensory
What is the epithelium of the trachea derived from?
ENDODERM. I should have just said the entire respiratory system’s epithlium and glands are endodermal origin, while pslancic mesoderm surrounds it for supporting cartilage (not tracheal cartilge), smooth muscle and connective tissue
What is an abnormal communication between trachea and esophagus?
Tracheal fistula
What are tracheoesophageal fistulas (the most common anomoly of lower resp tract) associated with?
esophageal atresia.
When and why do you see polyhydrmnios?
Tracheoesophageal fistula b/c amniotic fluid can’t pass to the stomach and intestines for absorption and subsequent transfer via the placenta to mother’s blood.
Do pneomnoia and pnemonitis happen with trachoesophageal fistula very often?
Absolutely. Food or gastric contents can enter lungs
Respiratory diverticulum development happens like how? (this is a broad card, didnt know what to do, but thought the info should be involved. Deal with it dB^| (that is the deal with it meme wearing a baseball hat)
Laryngotracheal groove —> laryngotracheal diverticulum —> respiratory bud —> primary bronchial buds —> secondary bronchial buds —> segmental branches (bronchopulmonary segments). The entire respiratory system comes from divirticulum
Where do bronchial buds grow into?
Pericardioperitoneal canals (remember that?).
Epithelial lining of the pericardioperitoneal folds is important why?
Becomes the visceral pleura and connective tissue and smooth muscle and cartilage associated with the lung. The splanchnic mesoderm
What is parietal pleura is derived from what?
Somatic mesoderm. From the body wall to make the parietal pleura.
What is an azygos lobe and what causes it?
When right lung (which is where azygos is) devos medial to azygos veina dn lung devo fails and agenesis of the lung (can’t develop)
When do you usually see lung hypoplasia?
Congenital Diaphragmatic Hernia (remember from CRRAB 1?). Failure of closure of the L pleuroperitoneal fold and abdominal stuff gets in way of lung devo.
What can oligohydramnios (not enough amniotic fluid) cause?
Pulmonary hypoplasia because the uterine wall can compress the fetal thorax wihtout that proteciton.
Bilateral Rneal Agenesis because of a lack of urine produciton reduces the amount of amniotic fluid
What is Potter’s Syndrome?
Pulmonary hypoplasia and bilateral renal agenesis. Can happen from oligohydramnios
Got to slide 39
coool
What bronchioles have alveoli in their walls?
Respiratory bronchioles. They then lead to alveolar sacs that are just packed full of those little CO2/O2 exchanging fuckers
What is stage 1 (of 4) of lung development?
Stage 1: Pseudoglandular period. Ductal elements are forming with no alveoli and vascular system is separated from ductal elements by connective tissue
Stage 2: Canalcular stage: resp passages are cranial to caudal, and vascularization of devo resp elements happens and resp is possible!
3: Terminal sac stage: epithelium of alveoli is
What is stage 2 (of 4) of lung development
Stage 2: Canalcular stage: resp passages are cranial to caudal, and vascularization of devo resp elements happens and resp is possible!
what is stage 3 of lung maturation?
Terminal sac stage (26 weeks to birth). epithelium of developing type 1, type 2 alveoli and capillaries and lymphatics are developing.
What is stage 4 of lung maturation?
Alveolar stage (33 weeks to 8 years after birth (note overlapped with stage 3). Respiratory membrane is sufficiently thin to allow efficient gas exchange. Alveoli number double from birth to age 8 (up to 300 million)
What are type 1 and type 2 alveoli?
Type 1 is gas exchange. Type 2 make surfactant
What does infant survival rely on respiratory wise?
Adequate vasculature and surfactant
What is the point of fetal breathing movements? (FBM)
help stimulate the lung development and and muscularature devo.
Half of the lung fluid is from amniotic fluid. How is it removed?
- throught the mouth and nose from pressure during vaginal delivery. 2. into pulmonary arteries, veins and capillaries. 3 into lymphatics
What is the name of the disease caused by deficiency of surfactant?
Haline membrane disease
What do you see in hyaline membrane disease?
surfactant deficiency causes protein rich exudate into the alveolar spaces and formation of haline membrane resulting in respiratory distress syndrome which causes 20% of infant deaths in newborn period
What stimulates development of lung production of surfactant?
Thytroxane
What can be administered during pregnancy to accelerate fetal lung development?
Glucocorticoids (Beta mechasone). Used if likelihood of premature birth
Difference between healthy and stillborn lungs?
Still born lungs sink b/c firm and fluid filled instead of air. Gosh darn sad.
3 important things to know about for the test?
Tracheoesophageal fold, hypoplasia and hyaline membrane disease
