13. Respiratory System and Thoracic Cavities Flashcards
Laryngotracheal groove forms from the 6th arch, is the primitive pharynx, on the outside of the groove what is it called? (2 names )
Called the laryngotracheal diverticulum or lung bud (respiratory diverticulum) outside of embryo
What is the orientation of the esophagus and the trachea at the beginning of formation?
the trachea is anterior to the esophagus
How are the trachea and the esophagus separated?
tracheoesophagela folds
There are indentation on either side of the tube, the folds will then fuse in the midline, it forms the?
tracheoesophageal septum, separating esophagus from the larynx
When are the laryngotracheal diverticulum and the tracheoesophageal septum formed?
4th and 5th week
What is important to notice of the tracheoesophageal ridge and why?
It is very long/longitudinal. Defects will be formed d/t it
Where does the larynx come from?
the forgut endoderm, laryngotracheal groove (6th pharyngeal arch (4/6 are considered together, there is no 5th arch))
What is the first thing seen in the formation of the larynx?
Bilateral arytenoid swellings, which are endoderm covered in mesenchyme (neural crest), which diverge into cartilage
What do the arytenoid swellings do?
They grow towards tongue, converting groove to T shaped opening called the glottis (opening/space for air to get through to vocal cords)
Hypobranchial/Hypopharyngeal eminence found in arches 3/4, looking at arch 4. What do you see forming in this area?
formation of the epiglottis
While the arytenoid swellings are converging, the endoderm proliferates and fills up the glottis, then undergoes apoptosis and that is when you get_____?
recanalization, which is complete by week 10, afterwards there is a space/opening to get into lungs
What else does recanalization form within the larynx?
Laryngeal ventricles (later) Vocal and vestibular folds
What congenital abnormality occurs when recanilization (apoptotic process) has failed during week 10. They present with asphyxia at the time of birth and have obstruction of the upper fetal airway?
Laryngeal Atresia
What congenital abnormality occurs when there is incomplete atresia and tissue between vocal folds, which block the glottis. Present with respiratory distress, unusual cry and stridor (high pitched cry)? Caused by failure of recanalization in week 10
Laryngeal webs
What congenital abnormality occurs when there is collapse of the supraglottic structures during inspiration (epiglottis, arytenoid cartilage). Mechanism unknown, making it difficult to breath.
Laryngomalacia