F - Embryo of the Respiratory System - Cole

Question 1

Early lung development regulated by

Answer 1

Location - TBX4 (from T-box transcription factor gene family)
Increased RA

Question 2

Development of lungs being?

Answer 2

Week 4

With formation of laryngeotracheal (respiratory) diverticulum

Question 3

What is the cause of tracheoesophageal fistula

Answer 3

Abnormal communication between trachea and esophagus

Improper formation of tracheoesophageal septum

Question 4

What does a chest X-ray of a tracheoesophageal fistula look like?

Answer 4

An air-filled pouch representing the proximal esophagus.

Distension of this proximal esophagus causing anterior displacement of the trachea

Question 5

Misexpression of Tbx4 causes what two things?

Answer 5

Ectopic endodermal budding and tracheo-esophageal fistula

Question 6

Symptoms of tracheoesophageal fistula?

Answer 6

Excessive salivation with choking, coughing and sneezing

When fed, swallow normally but begin to cough and struggle as fluid returns through nose and mouth

Question 7

2 other types of abnormalities

Answer 7

Laryngotracheoesophageal clefts and tracheal stenosis

Question 8

Development of bronchi

Answer 8

Week 5 - divide into 2 bronchial buds that will become primary bronchi

Question 9

What week do the lobes of lungs development?

Answer 9

External aspect - week 6

Advanced stage - end of week 6

Question 10

What does the splanchnic mesoderm differentiate into?

Answer 10

Smooth muscle, nerves and blood vessels of the lungs

Question 11

The bronchioles are modeled to optimize what?

Answer 11

Max surface area for gas exchange
To minimize resistance to airflow
–max area with minimum resistance

Question 12

Describe the embryonic stage of lung development

Answer 12

Weeks 4-7
Lungs grow into pleural cavities
Differentiation of pleura

Question 13

Describe (Pseudo)Glandular Stage

Answer 13

Weeks 8-16
NO respiratory components, gas exchange
Resemble a gland
Induction of vasculogenesis of pulmonary veins mediated by VEGF

Question 14

What mediates the induction of vasuclogenesis of pulmonary veins?

Answer 14

VEGF

Question 15

Describe the Canalicular stage of lung development

Answer 15

Weeks 17-26
Formation of primitive alveoli
Capillaries in walls

Question 16

Type I cells form part of what?

Answer 16

The blood-air barrier

Question 17

Type II cells job?

Answer 17

Secretory cells produce surfactant
Reduces surface tension
Facilitates alveolar expansion

Question 18

How much alveoli is formed after birth?

Answer 18

90%

-primary mechanism is septation of pre-existing alveoli

Question 19

During what lung development phase is the fetus viable?

Answer 19

Canalicular phase

Question 20

Misexpression of Fgf10 causes

Answer 20

Ectopic endodermal budding, tracheo-esophageal fistula and ectopic Tbx4 expression

Question 21

Characteristics of infant respiratory distress syndrome

Answer 21

Primarily in immature lung
60% in < 28 weeks gestation
5% in > 37 weeks gestation
Labored breathing, def or absence of surfactant
Histo - alveoli are collapsed, RBCs accumulate

Question 22

Atelectasis

Answer 22

The incomplete expansion or collapse of parts of or a whole lung

Question 23

Hyaline membrane disease

Answer 23

Alveoli filled with debris in uniform distribution

Looks like ground glass on chest x-ray

Question 24

Congenital neonatal emphysema

Answer 24

Misnomer - NO alveolar destruction
Over-distension of one or more lobes of lung
Caused by collapsed bronchi, bronchial cartilage doesn’t develop

Question 25

Congenital bronchial cysts

Answer 25

Bronchiesctasis
Honeycomb on x-ray
Airways are baggy and enlarged with mucus pockets

Question 26

Pulmonary hypoplasia

Answer 26

Poorly developed bronchial tree
-partial or total
Bilateral renal agenesis
Insufficient amniotic fluid (oligohydraminos)

Question 27

What is oligohydramnios

Answer 27

Low volume of amniotic fluid

Associated with renal a genesis and obstructive uropathy

Question 28

Potter syndrome

Answer 28

Pulmonary hypoplasia

Question 29

Polyhydramnios

Answer 29

High volume of amniotic fluid

Associated with CNS anomalies and esophageal atresia

Question 30

What are nerve roots associated with the phrenic n.?

Answer 30

C3-5

Keep the diaphragm alive - starting week 4

Question 31

Congenital diaphragmatic hernias

Answer 31

Abd contents into pleural cavity
Failure of pleuroperitoneal membranes to fuse with other components
Most common on posterolateral side

Question 32

Symptoms of congenital diaphragmatic hernias

Answer 32

Flat abdomen, breathlessness and cyanosis