Respiratory System Development

Question 1

What things develop from the endoderm of the respiratory diverticulum?

Answer 1

• Alveolar type I pneumocytes
• ciliated cuboidal epithelium of the bronchioles
• clara cells
• pseudostratified column ciliated epithelium
• seromucous glands of the trachea

Question 2

The mesenchyme surrounding the lung buds determines the pattern of their growth and gives rise to the:

Answer 2

Smooth muscles

Question 3

What structure is derived from neural crest ectoderm?

Answer 3

Laryngeal cartilage

Question 4

What is a tracheoesophageal fistula?

Answer 4

An abnormal communication (fistula) between the trachea and the esophagus. Most common anomaly of the lower respiratory tract.

Question 5

What is a Tracheoesophageal fistula frequently associated with?

Answer 5

Esophageal atresia

Question 6

What causes tracheoesophageal fistula?

Answer 6

Results from abnormal partitioning of the largyngotracheal tube by the tracheoesophageal septum, producing an abnormal communication between the trachea and esophagus.

Question 7

What happens in the fetus due to a tracheoesophageal fistula?

Answer 7

Amniotic fluid accumulates (polyhydramnios) because it cannot pass through the stomach and intestines for absorption and subsequent transfer via the placenta to the mother’s blood.

Question 8

What is derived from splanchnic mesoderm?

Answer 8

Vascular tissue of the tracheal adventitia

Question 9

What developing structure serves to separate the trachea from the esophagus?

Answer 9

Tracheoesophageal septum

Question 10

What is an Azygos lobe?

Answer 10

Part of superior lobe of right lung grows medial to azygos vein instead of lateral to it. (there is a little lobe created by the azygos vein pressing into the lung)

Question 11

What is Agenesis of the lungs?

Answer 11

Failure of the lung bud to develop (bilateral agenesis) or unilateral lung ageless where only one lung develops

Question 12

What is lung hypoplasia usually associated with?

Answer 12

Congenital diaphragmatic hernia.

Question 13

What a classic cause of pulmonary hypoplasia (other than congenital diaphragmatic hernia)?

Answer 13

Oligohydramnios - a condition in which there is an insufficient amount of amniotic fluid; presumably, oligohydramnios causes pulmonary hypoplasia by allowing the uterine wall to compress the fetal thorax.

Question 14

What does bilateral renal agenesis cause?

Answer 14

Oligohydramnios because a lack of urine production reduces the amount of amniotic fluid.

Question 15

What is Potter’s syndrome?

Answer 15

Pulmonary hypoplasia and bilateral renal agenesis.

Question 16

What gives rise to the cartilaginous tissue that comprises the walls of the trachea, bronchi and bronchioles?

Answer 16

Splanchnic mesoderm

Question 17

Into what part of the intraembryonic coelom doe the developing lung bud grow?

Answer 17

Pericardioperitoneal canal

Question 18

What are fetal breathing movements (FBMs)?

Answer 18

They occur prior to birth and are essential for normal lung development. FBMs stimulates lung development and facilitates development of respiratory musculature.

Question 19

What is Aeration at birth?

Answer 19

It is the rapid replacement of intra-alveolar fluid by air. One half of the lung fluid is derived from the lung tissue itself, while the remaining fluid in the alveoli is amniotic fluid.
Removal of the Amniotic fluid occurs:
(1) through the mouth and nose by pressure on the thorax during vaginal delivery
(2) into the pulmonary arteries, veins and capillaries
and (3) into the lymphatics.

Question 20

What is hyaline membrane disease?

Answer 20

Caused by a deficiency of surfactant and injury to the alveolar wall resulting in a protein-rich, fibrin-rich exudations into the alveolar spaces and formation of hyaline membranes (result is respiratory distress syndrome)

Question 21

How many infant deaths does respiratory distress syndrome account for?

Answer 21

20% of all infant deaths in the newborn period.

Question 22

What is used during pregnancy to accelerate fetal lung development?

Answer 22

Glucocorticoids (beta-methasone) - Accelerates development of type II pneumocytes so they produce more surfactant

Question 23

What reduces the severity of respiratory distress syndrome and neonatal mortality?

Answer 23

Administration of exogenous surfactant (surfactant replacement therapy)

Question 24

What cells are responsible for production of pulmonary surfactant?

Answer 24

Type II pneumocytes

Question 25

At what week in human fetal development does pulmonary surfactant formation begin to occur?

Answer 25

20 weeks

Question 26

What contributes to the fluid component of the lungs at birth?

Answer 26

Amniotic fluid, blood vessels and lymphatics of the lung, seromucous glands, tracheal glands

Question 27

Which of the following stimulates the production of surfactant during intrauterine life?

Answer 27

Glucocorticoids

Question 28

Ultrasonography indicates oligohydramnios. What abnormality may be present in the infant at birth?

Answer 28

Lung hypoplasia

Question 29

Newborn infant gagging and with cyanosis. Can’t catheterize the stomach. Air in the stomach. What is the diagnosis?

Answer 29

Tracheoesophageal fistula