Respiratory Embryology

Question 1

The respiratory system starts as a median outgrowth know as the?

Answer 1

Laryngotracheal groove

Question 2

What forms the pulmonary epithelium and glands of larynx, trachea and bronchi?

Answer 2

Endoderm of laryngotracheal groove

Question 3

What forms the CT, cartilage, and smooth muscle of the respiratory system?

Answer 3

Splanchnic mesoderm from lateral plate

Question 4

The laryngotracheal groove will evaginate to form?

When this new structure elongates it’s invested with?

Answer 4

1) Laryngotracheal diverticulum (lung bud)

2) Splanchnic mesenchyme

Question 5

As the tracheoesophageal folds develop, they fuse to from?
What is this structures role?
Around what time does this happen?

Answer 5

1) Tracheoesophageal septum
2) Prevents aspiration during eating/drinking
3) End of 5th week

Question 6

The foregut is formed during?

It gives rise to?

Answer 6

1) Week 4

2) Upper GI and lungs

Question 7

During the development of the larynx, mesenchyme of 4th and 6th pairs of PAs (NCC derived) creates the?

Answer 7

Cartilages

Question 8

During the development of the larynx, mesenchyme produces?

What does this structure do?

Answer 8

1) Paired arytenoid swellings

2) Convert primordial glottis into a T-shaped laryngeal inlet

Question 9

During the development of the larynx, recanalization occurs by the?
Laryngeal ventricles form during recanalization and are bounded by folds of mucous membrane to form?

Answer 9

1) 10th week

2) Vocal folds (cords) and vestibular folds

Question 10

What does the epiglottis develop from?

Answer 10

Hypopharyngeal eminence produced from endoderm of 3-4th PAs

Question 11

In neonates, the epiglottis is in contact with?

What does this result in?

Answer 11

1) Soft palate

2) Separates respiratory and digestive tracts during nursing

Question 12

What allows you to start feeding a child more liquid and solid foods?

Answer 12

The laryngeal descent over the first 2 years

Question 13

Laryngeal atresia is a rare birth defect that results from?

Answer 13

Failure of recanalization of the larynx

Question 14

Laryngeal atresia can result in what physical presenting symptoms?
How is laryngeal atresia treated?

Answer 14

1) Congenital high airway obstruction syndrome (CHAOS)

2) Endoscopic dilation of the laryngeal web

Question 15

What fails in a tracheoesophageal fistula?
In what week does the failure occur?
What causes them?
What do they lead to?

Answer 15

1) Tracheoesophageal septation
2) Week 5
3) Failure of foregut endoderm to proliferate rapidly
4) Food will aspirate into lungs

Question 16

What are polyhydramnios?

What is it caused by?

Answer 16

1) Excess amniotic fluid

2) Esophageal atresia or tracheoesophageal fistula

Question 17

During lung development the distal end of laryngotracheal diverticulum enlarges to form?
The bud grows ventrocaudal and bifurcates to form?
They grow in the?
When does it branch?

Answer 17

1) Respiratory bud
2) Primary bronchial buds
3) Pericardioperitoneal canals
4) 5th week

Question 18

The branching pattern of the lung endoderm is regulated by?

Answer 18

Splanchnic mesenchyme

Question 19

The visceral pleura is what portion of lateral plate mesenchyme?
The parietal pleura is what portion of lateral plate mesenchyme?

Answer 19

1) Splanchnic

2) Somatic

Question 20

During the pseudoglandular stage of lung maturation, what part of the lung is developed?
What weeks does the pseudoglandular stage fall under?

Answer 20

1) Terminal bronchioles

2) 5-17 weeks

Question 21

What forms during the canalicular stage of lung maturation?

What weeks does the canalicular stage fall under?

Answer 21

1) Respiratory bronchioles and primordial alveolar

2) 16-25 weeks

Question 22

What forms during the terminal sac stage of lung maturation?

What weeks does the terminal sac stage fall under?

Answer 22

1) Type I/II pneumocytes appear

2) 24 weeks to birth

Question 23

What forms during the alveolar stage of lung maturation?

What weeks does the alveolar stage fall under?

Answer 23

1) Mature alveoli and capillaries

2) 32 weeks to 8 years

Question 24

Can the fetus survive in the following stages of lung maturation:

1) pseudoglandular stage
2) canalicular stage
3) terminal sac stage
4) alveolar stage

Answer 24

1) No
2) Some can
3) Yes
4) Yes

Question 25

Fetal Breathing Movements are forceful enough to cause?

Answer 25

Aspiration of amniotic fluid

Question 26

At birth, amniotic fluid is reabsorbed by?

When fluid is reabsorbed from alveolar sacs, what remains on alveolar cell membranes?

Answer 26

1) Blood and lymph

2) Surfactant

Question 27

What is pulmonary agenesis?

Answer 27

Respiratory bud fails to split resulting in complete absence of lung or lobe

Question 28

What is oligohydramnios?

Oligohydramnios after 26 weeks increases the risk of?

Answer 28

1) Insufficient amniotic fluid production

2) Pulmonary hypoplasia

Question 29

What is the major cause of respiratory distress syndrome?
What effect does this have on lungs?
What are some signs and symptoms of respiratory distress syndrome?

Answer 29

1) Surfactant deficiency
2) They are underinflated
3) Tachypnea, grunting and cyanosis

Question 30

What are congenital lung cysts filled with?

What are congenital lung cysts though to be formed by?

Answer 30

1) Fluid or air

2) Dilation of terminal bronchi

Question 31

Pulmonary surfactant is produced from what cells?

Answer 31

Type II alveolar epithelial cells

Question 32

The trachea is lined with what type of epithelium?

Answer 32

Pseudostratified ciliated columnar epithelium with goblet cells