Embryology Flashcards
Pseudoglandular Stage of Lung Development
Weeks 5-17 where lungs take on a glandular appearance; represents a period of rapid branching of the pulmonary tree w/ mucous glands present by week 18
Canalicular Stage of Lung Development
Occurs during Week 16-24 when lungs get a canal-like appearance; capillary beds expand and endothelium thins to allow for gas exchange
-Production of surfactant begins in this stage; accelerated by presence of glucocorticoids, decreased by neonatal insulin prod. in response to maternal diabetes
Saccular Stage of Lung Development
Weeks 24-38 when lung cell proliferation slows but Type II pneumocyte fnxn increases
Alveolar Stage of Lung Development
Occurs from 36-weeks to 3 years; lungs develop large increase in pneumocytes (especially type II) as well as a decrease in smooth muscle and PVR
Factors needed for alveolar development
VEGF, estrogen, Retinol
-testosterone actually decreases lung development
Surfactant Protein-A
Most abundant type of surfactant that is recycled by Type II pneumos; also act as an opsonin important in warding off infxn
-Deficiency is still compatible w/ life
Surfactant Protein B
Enhances the spread of the surfactant monolayer; deficiencies are not compatible w/ life
-Can tell because these babies do not respond when given surfactant administration
Surfactant Protein C
Most hydrophobic surfactant protein; requires activation by Surfactant B**
Main fnxn: recruit other lipids to the surfactant monolayer
-Deficiencies are compatible w/ life but may develop early onset interstitial fibrosis
Surfactant Protein D
Largest of the surfactants that mainly fnxns as a component of the innate immune system; can be found in other organs
Surfactant Inactivation
Can occur in aspiration, meconium, pneumonia, or swallowed blood
Betamethasone
Increases the surfactant prod. of Type II pneumos
Maternal Admin. =» decrease fetal body and lung growth that worsens w/ each dose
Fetal admin. =» Improves lung maturation w/ no effect on lung growth
Transient Tachypnea of Newborn
Failure of fetal lung fluid to be resorbed during delivery; baby presents w/ mild RD
Assoc. w/ prematurity, C-sec, umbilical cord prolapse
***See starbust pattern on CXR
Tx: O2 support; great success
Respiratory Distress Syndrome
Baby prevents w/ severe RD due to decreased surfactant production =» hyaline membrane formation w/ destruction of alveoli
Tx: Bovine SURFACTANT
Neonatal Pneumothorax
Vaginal delivery w/ broad-shouldered baby (shoulder dystocia)
Congenital Diaphragmatic Hernia
CXR will show intestines in chest; baby presents w/ mild RD
Tx: Surgery/supportive