Embryonic Development of Body Cavities

By the end of this lecture, time spent in the dissecting room, and further private study you should be able to: Describe the embryonic development of the ______ and bronchi

Describe the embryonic development of the lungs and ______

Describe the embryonic development of the ______

During development, the diaphragm forms to separate the thoracic and abdominopelvic ______.

The formation of the tracheoesophageal septum separates the ______ and oesophagus.

The laryngeal muscles and cartilages come from the fusing of mesenchyme from arches 4 and ______.

MD3001 2023 7 Development of body cavities The mesoderm develops into distinct parts, termed paraxial, intermediate and lateral plate mesoderm Lateral plate mesoderm is divided into parietal and ______ layer by the development of intra embryonic coelom Parietal layer forms the body walls Visceral layer forms connective tissue of respiratory systems

MD3001 2023 8 Development of body cavities The mesoderm develops into distinct parts, termed paraxial, intermediate and lateral plate mesoderm Lateral plate mesoderm is divided into ______ (somatic) and visceral(splanchnic) layers by the development of intra embryonic coelom

MD3001 2023 10 Development of body cavities The embryonic “disc” folds in two planes – cranio-caudally and laterally Lateral folding causes closing of the body walls and “entrapment” of intraembryonic coelom into a closed body cavity Cavity lined by somatic LP mesoderm, gut tube/mesentery by ______ LP mesoderm

Congenital abnormalities Oesophageal atresia and tracheoesophageal fistula 1 in 3000 births, defect in partitioning of tracheoesophageal septum May be diagnosed in utero (excess amniotic fluid) Surgical correction after birth May accompany other defects: – VACTERL association (Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula, Esophageal atresia, Renal anomalies, and Limb defects ______ ______ 2023 4% 4% 90% 1% 1%

Congenital abnormalities Respiratory distress syndrome Premature birth, insufficient surfactant Alveoli are therefore in a collapsed state 20% of newborn mortality Managed by artificial surfactant or giving mother glucocorticoids to stimulate surfactant Congenital pulmonary airway malformation 1 in 30,000 births A lobe is replaced by non functional cystic tissue Often asymptomatic (75%), surgical excision after birth Supernumerary lobules Ectopic lobules ______ ______ 2023

Development of the lower respiratory tract in several stages. What is the first stage of this process? ______

The final stage of lung development involves Divisions of the alveoli, which continues after birth. Until what age does this process occur? ______

Congenital abnormalities Oesophageal atresia and tracheoesophageal fistula 1 in 3000 births, defect in partitioning of tracheoesophageal septum May be diagnosed in utero (excess amniotic fluid) Surgical correction after birth May accompany other defects: – VACTERL association (Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula, Esophageal atresia, Renal anomalies, and Limb defects MD3001 2023 ______ ______ ______ 1% 1%

Congenital abnormalities Respiratory distress syndrome Premature birth, insufficient surfactant Alveoli are therefore in a collapsed state 20% of newborn mortality Managed by artificial surfactant or giving mother glucocorticoids to stimulate surfactant Congenital pulmonary airway malformation 1 in 30,000 births A lobe is replaced by non functional cystic tissue Often asymptomatic (75%), surgical excision after birth Supernumerary lobules Ectopic lobules ______ ______ 2023 30 SBA style q