Flashcards in Respiratory Embryo Deck (35):
When does gas exchange happen in a baby?
Not until after birth (transitional circulation)
What layer is the lining of the respiratory system from?
What are the muscle, cartilage, vessels, and connective tissue of the respiratory system from?
What is the nervous system part of the respiratory system from?
What is the lung bud?
Out-pouching from the ventral wall of the cranial portion of the endoderm (foregut)
What is the innervation of the larynx?
superior laryngeal and recurrent laryngeal nerves
What are the cartilage and muscles derived from in the larynx?
4th and 6th pharyngeal arches
Where does the larynx open into the pharynx? What part of the respiratory tree is the larynx?
Btn the 4th & 6th pharyngeal arches; larynx is most proximal portion of the respiratory tree
How are the trachea and esophagus divided?
Two ridges form to separate them - tracheo-oesophageal septum
What’s a tracheoesophageal fistula? What’s a fistula in general? What’s an esophageal
A TEF is an abnormal connection (fistula) between the esophagus and the trachea. A fistula in general is an abnormal communication between two epithelialized surfaces. Congenital TEF can arise due to a failed fusion of the tracheoesophageal ridges during the 3rd week of embryological
development. VACTERL association.
Esophageal atresia - the esophagus ends in a blind-ended
pouch rather than connecting normally to the stomach
What is the VACTERL association with TEF?
The trachea buds into the right and left main bronchi in the 5th week. What do the right and
left main bronchi branch into?
R: 3 secondary bronchi, 10 tertiary (segmental) bronchi. L: 2 secondary bronchi, 8 segmental
What are heterotaxy syndromes?
Heterotaxy syndrome is a disorder that results in certain organs forming on the opposite side
of the body. For example, instead of the heart normally forming on the left side of the chest, it
will be located on the right side. Heterotaxy has been known to affect the development of the
heart, liver, lungs, intestines, and spleen.
What’s in the pseudoglandular period (5-16 wks)?
Terminal bronchioles present
What’s in the canalicular period (16-26 wks)?
Respiratory bronchioles and alveolar ducts
What’s in the terminal sac period (26 wks to birth)?
Terminal sacs, capillaries are close
What are the four periods of lung maturation?
Pseudoglandular (5-16 wks), canalicular period (16-26 wks), terminal sac period (26 wks to
birth), alveolar period (8 mo to childhood)
What do we get if there’s abnormal budding (defective mesenchyme) in respiratory
Bronchogenic cysts; respiratory lined cysts that are adjacent to the respiratory tree but not
If there is abnormal signaling in bronchial epithelium-mesenchyme communication, what can
CCAM: Congenital Cystic Adenomatoid Malformation
Explain the malformation histology of Cystic Adenomatoid (CCAM)? What can we diagnose
Increased terminal bronchiolar tissue, intercommunication cysts lined by respiratory
epithelium, restricted to one part of one lung. Diagnosed by prenatal ultrasonography or fetal
What happens when the esophagus is compressed from fetal lung lesions?
What happens when the lung is compressed from fetal lung lesions?
What happens when the vena cava and heart are compressed by fetal lung lesions?
hydrops (fetal heart failure)
Abnormal lung budding leads to ______
Failure of mesenchymal maturation results in _______
Persistent systemic circulation to the lung
What’s a pulmonary sequestration?
Lung mass with: blood supply from abnormal systemic artery & no anatomically normal
What’s an extralobar pulmonary sequestration?
It’s separate from the normal lung usually in the posterior/lower chest; systemic artery,
venous drainage to azygous, hemiazygous, portal or pulmonary veins
What’s an intralobar pulmonary sequestration?
It’s within the visceral pleural envelope, an artery from descending or abdominal aorta,
venous drainage to pulmonary veins
With respect to lung maturation, there is a steady increase in # of ______ from 7th month to
What can lung maturation and surfactant production be stimulated by?
Steriod administration; artificial surfactant can also be administered
Initially the pleural and peritoneal cavities are one completely open cavity. What’s the last
thing to close?
Pleuroperitoneal canal (posterolateral)
Does fetal breathing movement occur before birth? Talk about fetal lung fluid.
the lungs actively produce fluid in-utero. Fetal breathing movement does occur before birth.
Amniotic fluid also assists with lung development in-utero. The fluid is expelled as the child
passes through the birth canal and with the first cry. The remaining fluid is absorbed by
pulmonary lymphatics leaving a coat of surfactant
What’s the origin for the pleura? If there is fluid in the pleural space and an abnormal
communication between the structures, is this a fistula?
Mesoderm; not a fistula since this is not epithelialized!
What is a congenital diaphragmatic hernia? Which side does it usually occur on?
CDH is a congenital malformation (birth defect) of the diaphragm. Malformation of the
diaphragm allows the abdominal organs to push into the proper lung formation. Newborns with
CDH often have severe respiratory distress; life-threatening pathology. Usually occurs on the left side – mortality is high, especially prenatally