Week 1 Flashcards
What portions of the body encompasses the upper respiratory tract?
nose, nasopharynx, and oropharynx
How is the lower respiratory system formed in early development?
Laryngotracheal diverticulum start to bud, then the lungs bud and finally the bronchials bud. Afterwards, the tracheoesophageal septum separates the laryngotracheal tube from the esophagus.
What layer of the embryo derives the laryngotracheal tube and esophagus?
visceral mesoderm
what layer of the embryo do the laryngeal epithelium and glands arise from?
endoderm
what layer are laryngeal muscles derived from?
somitomeric mesoderm of pharyngeal arches 4 and 6
what layer is the laryngeal connective tissue and cartilage derived from?
mesoderm
what layer is the tracheal epithelium and glands derived from?
endoderm
what layer is the tracheal cartilage, smooth muscle and connective tissue derived from?
mesoderm
what is an tracheoesophageal fistula? clinical features?
a connection between the trachea and the esophagus. excessive accumulation of saliva or muscus in the nose or mouth; episodes of gagging and cyanosis after swallowing milk; abdominal distention after crying; reflux of gastric contents into lungs causing pneumonitis.
what is the most common type of tracheoesophageal fistula?
esophageal atresia with a distal ended tracheoesophageal fistula.
what is the diagnostic features of tracheoesophageal fistulas?
inability to pass a catheter into the stomach and x-rays demonstrate air in the infant’s stomach.
what is tracheal stenosis and atresia
are rare malformations of narrowing or closure of tracheal lumen and is usually associated with TE fistula.
what is a tracheal diverticulum?
is a rare malformation in which a blind bronchus-like projection occurs off the trachea
what does the visceral mesoderm and somatic mesoderm become in bronchial development in an embryo?
visceral mesoderm: visceral pleura
Somatic mesoderm: parietal pleura
what is congenital neonatal emphysema?
overdistention with air of one or more lobes of the lung due a bronchi being collapse because bronchial cartilage development failed. air can be inspired but not expired.
what is congenital bronchial cysts (bronchiectasis)?
caused by dilation of bronchi; cysts may be solitary or multiple, filled with air or fluid; honeycomb on x-ray
what are the periods of lung development in embryo?
glandular period
canalicular period
terminal sac period
alveolar period
Describe what occurs during the glandular period of lung development?
weeks 5-17: branching of endodermal tubules that have the air conducting system, but gas exchange cannot occur yet therefore no respiration can occur. premature fetus dies during this period.
what occurs during the canalicular period of lung development in an embryo?
weeks 13-25: respiratory bronchials and terminal sacs develop; premature fetuses born less than 20 weeks rarely survive.
what occurs during the terminal sac period?
terminal sac and vascularization increases greatly. differentiation of TYPE 1 Pneumocytes (blood-air barrier cells) and TYPE 2 pneumocytes (produce surfactant) begins.
capillaries make contact with type 1 pneumocytes which allows respiration
premature fetuses born between 25-28 weeks can survive with ICU but need surfactant
What occurs during the alveolar period in lung development?
week 29-8 years old: by age 8 adult complement of alveoli is reached, terminal sacs develop into mature alveolar ducts and alveoli; mature blood-air barrier is established.
What is respiratory distress syndrome?
it is caused by a deficiency or absence of surfactant
What is pulmonary agenesis?
is complete absence of lungs, bronchi, and vasculature due to rare condition where bronchia buds fail to develop.
what is pulmonary hypoplasia?
is a poorly developed bronchial tree with abnormal histology,
