Term
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Definition
Starts as an outpouch of the ventral wall of the foregut (respiratory diverticulum).
1. Epithelial cells - endodermal origin
2. Muscle, cartilage, vessels, connective tissue etc. - from the splanchnic mesoderm. |
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Term
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Definition
Determines where respiratory and GI split occurs.
Sprouts between the 4th and 6th pharyngeal pouches to form the trachea and lung buds. Comes off of the esophagus and forms the tracheal-esophageal septum. |
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Term
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Definition
Proximal portion of the respiratory tree
opens into the pharynx between the fourth and sixth pharyngeal arches.
cartilages and muscles - derived from the 4th and 6th pharyngeal arches
Innervation - superior laryngeal and recurrent laryngeal nerves |
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Term
| Branching of tracheobronchal tree |
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Definition
Left lung:
Trachea->Left Bronchus->2 Lobar Bronchi->8 segmental bronchi
Right lung:
Trachea-> Right bronchi-> 3 lobar bronchi-> 10 segmental bronchi.
Lobar bronchi are enveloped by pleura to form fissures and lobes of lungs. |
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Term
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Definition
Lung develops until 8 years of age, reason why pollutants are more harmful for children.
Need division of nerves, vessels, and cartilage to go along with developing lung.
Necessitates interaction between mesenchyme and epithelium moderated by members of the FGF family.
Grow out ventrally and caudally and are surrounded by pleura. |
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Term
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Definition
1. Pseudoglandular period (develops up to terminal bronchioles)
2. Canalicular Period (Respiratory Bronchioles and Alveolar Ducts)
3. Terminal Sac Period (Terminal sacs, capillaries are close enough for gas exchange)
4. Alveolar Period (Well developed epithelial-endothelial contacts) |
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Term
| Limit of fetal viability without ventilator |
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Definition
| Occurs at the terminal sac period, where the capillaries are close enough for efficient gas diffusion. |
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Term
| Lung maturation process during and after the terminal sac period |
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Definition
Steady increase in number of alveolar sacs from 7th month to school age.
Type I alveolar cells become thinner and nuclei move to thick alveolar wall, better gas exchange
Intimate epithelial-endothelial contact, capillaries getting closer. |
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Term
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Definition
The lungs actively produce fluid in-utero.
Fetal breathing movement occurs before birth.
Amniotic fluid also assists with lung development in-utero.
The fluid is expelled as the child passes through the birth canal and with the first cry.
The remaining fluid is absorbed by pulmonary lymphatics leaving a coating of surfactant.
Paralyzed fetuses don’t have lung growth due to no breathing movements, no flow, no growth. Major component of amniotic fluid: fetal urine, for fluid conservation. When fetus not making enough urine, lungs will not develop well, important in balance of fluids. |
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Term
| Esophageal Atresia and Tracheo-esophageal Fistula (TEF) |
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Definition
Improper alignment of esophago-tracheal septum.
Occurs in 1/3000 – 4500 births
Associated with other congenital anomalies
Cardiac anomalies in 35%
Most common case: Septum doesn’t divide all the way, veers off to disconnect the distal esophagus from the proximal, distal still attached to trachea. Creates atresia: blockage and loss of activity and fistula: abnormal communication between one epithelial lining and another. Drooling saliva, can’t feed. Gastric juices can come into trachea, creates pneumonia. Can diagnose in utero, stomach doesn’t develop. |
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Term
| Treatment for Tracheoesophageal Fistula |
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Definition
Evaluate for other anomalies
Prevent aspiration
Enteral Access
Restore continuity: Disconnect esophagus from trachea and connect two esophogeal portions together. |
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Term
Congenital Cystic Adenomatoid Malformation
(CCAM) |
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Definition
| Abnormal branching of trachea creates cysts. With improper division, fluid in lungs have nowhere to go, can’t reach trachea, fluid builds up and creates cysts. May compress heart (heart failure), lungs, or esophagus. |
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Term
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Definition
Stocker Classification
Type I: some cysts > 1 cm
Type II: cysts but < 1 cm
Type II: solid variant (tiny cysts like sponge) |
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Term
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Definition
Abnormal budding: aberrant/absent bronchi
Failure of mesenchymal maturation: persistent systemic circulation
Can be intralobar or extralobar sequestration |
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Term
| Extralobar pulmonary sequestration |
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Definition
Extralobar
Separate from normal lung
posterior/lower chest
1/20 below diaphragm
Systemic artery
venous drainage to azygous, hemiazygous, portal or pulmonary veins |
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Term
| Intralobar Pulmonary Sequestration |
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Definition
Within the visceral pleural envelope
Typically post/lateral segment LL
Artery from descending or abdominal aorta
venous drainage to pulmonary veins |
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Term
| Congenital Diaphragmatic Hernia |
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Definition
Occurs 1:4,000 live births
Most commonly on L side (90%)
Associated pulmonary hypoplasia because abdominal viscera impedes growth of the lungs. Main cause of death.
Associated malrotation |
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Term
| Fetoscopic Tracheal Occlusion (FETO) |
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Definition
| Treatment of Congenital Diaphragmatic Hernia: block the trachea to increase pressure in the lung. The increased pressure in the lung causes it to grow. |
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