Embryology of respiratory system Flashcards
When does primordium of resp system appear?
4 weeks from ventral wall of foregut
Where does epithelium of internal lining of larynx and trachea derive from?
Endoderm
Where are the muscular and cartilaginous components of trachea and lungs derived from?
splanchnic mesoderm
laryngeal orifice
Allows open communication between respiratory primordium and pharynx
Esophagotracheal septum
divides foregut into dorsal portion for esophagus and ventral portion for trachea and lung buds
Esophagotracheal ridges
Sep diverticulum from foregut
What results in laryngeal orifice changing shape?
Rapid proliferation of mesenchyme
Laryngeal ventricles form when
vacuolization and recanalization occur
False and true vocal folds
Formed by folds of tissue that bind laryngeal ventricles
Superior laryngeal nerve
innervates 4th branchial arch
Recurrent laryngeal nerve
innervates 6th branchial arch
Lung buds penetrate into this cavity
Pericardioperitoneal canal
Pleuropericardial folds
Sep canals from peritoneal and pericardial cavities
Mesoderm develops into
Visceral pleura
Somatic mesoderm develops into
Parietal pleura
Alveolar epithelial cells (type 1)
become gradually thinner so that surrounding capillaries protrude into alveolar sacs forming blood air barrier
Alveolar epithelial cells (type 2)
surfuctant producers which lower surface tension at air-alveolar interface
When does the amount of surfactant increase significantly?
Last 2 weeks before birth
Respiratory distress syndrome
Insufficient surfactant, air blood tension becomes too high, alveoli collapse
Hyaline membrane diseases
Partially collapsed alveoli contain fluid with high protein content, many hyaline membranes
Stillborn infant
Lung fluid is not resorbed
Ectopic lung lobes
arise from trachea or oesophagus-additional resp buds of foregut which dev independently
Congenital cysts of lung
dilation of terminal or larger bronchi
Supernumerary lobules
Abnormal divisions of bronchial tree
