When the heart is folded down to be below the head, the foregut is created between the heart at the abd wall
How does respiratory system development begin in the embryo?
positioning of the lung primordium and the primary lung bud formation
Summarize the early stage of lung formation
mechanism of bronchial branching and cytodifferentiation
Summarize the late stage of lung formation
TBX4 from T-box transciption factor family, also retinoic acid
What induces the laryngeotracheal divertriculum to grow out of the foregut towards the heart?
What seperates the esophagus (digestive) from the trachea (respiratory)?
What is an improper communication btw the esophagus and the trachea?
excess drool, choking, coughing, sneezing. Hungry but regergitate anything swallowed. Cyanosis and halted breathing may result.
What is the clinical presentation of tracheoesophageal fistula?
When do the left and right lung buds develop into 2 bronchial buds?
visceral pleura lines the lungs, parietal plura lines the pleural cavity
What lines the lungs and the pleural cavity?
airway segment length is never more than x3 its diameter
How are resp segments designed to maximize area and minimize resistance?
weeks 4-7. From resp diverticulum formation to formation of all major bronchiopulmonary segments. Lungs grow into pleural cavities. Pleura differentiates.
When is the embryonic stage of lung development and what occurs during it?
weeks 8-16. VEGF induces formation of pulm veins. Major growth of duct system in bronchopulm segments. Histologically, this stage looks like (false) glands.
When is the Pseudoglandular Stage of lung development and what occurs during it?
week 17-28. Formation of resp bronchioles and terminal sacs/primitive alveoli. Vascularization continues. Differentiation of type I and II pneumocytes occurs, first time when surfactant can be made.
When is the Canalicular Stage of lung development and what occurs during it?
28 weeks or later
What period do fetuses need to be in to be viable? (according to boards)
90% formed after birth
When do the majority of alveoli form?
What gene causes ectopic endodermal budding/ectopic lung lobes?
deficiency or absence of surfactant
What causes Infant Respiratory Distress Syndrome?
What is the incomplete expansion or collapse of parts or a whole lung?
hyaline fibrin-rich membranes made of damaged alveolar cells, cellular debris, edema, RBCs, collapsed alveoli
Histologically, what is seen in Infant Respiratory Distress Syndrome?
bronchial cartilage doesn't develop leading to overdistension of one or more lung lobes with air
Describe Congenital Neonatal Emphysema
honeycomb appearance on xray, baggy and enlarged airways with mucous pockets
Describe the presentation of Congenital Bronchial Cysts
What is the partial or complete absence of lungs, bronchi and/or vasculature?
What is the poor development of the bronchial tree?
Renal agenesis, oligohydraminos, Potter's Syndrome
What diseases are assoc w/ Pulmonary Hypoplasia?
What separates the abdominal cavity from the pleural cavities?
What separates the pleural cavities from the pericardial cavity?
What seperates the abdominal cavity from the thoracic cavity?
septum transversum forms the central tendon, pleuroperitoneal membranes from somatic mesoderm of dorsolateral body wall, crura from mesenchyme around the foregut
What does the diaphram form from?
What nerve innervates the diaphram?
Congenital Diaphragmatic Hernias
Failure of pleuroperitoneal membrane to fully fuse allows herniation of abdominal contents into the pleural cavities
flat abdomen, breathlessness, cyanosis
What is the clinical presentation of Congenital Diaphragmatic Hernias?