Embryology of Respi-Gitelman

Question 1

From where are the lungs originated?

Answer 1

From diverticulum off of the primitive gut.

Question 2

What is the general composition of the primitive gut and the respiratory system?

Answer 2

Endoderm and visceral mesoderm.

Question 3

What constitutes the blood/air barrier?

Answer 3

1. Alveolar squamous epithelial cell, 2. Capillary Endothelium, 3. Basal lamina (fused)

Question 4

Where are lamella bodies found?

Answer 4

Inside Type II pneumocytes.

Question 5

What is the origin of the tracheoesophageal septum?

Answer 5

Visceral mesoderm around endoderm grows up between the main pharyngeal tube and the laryngeotracheal diverticulum. Becomes muscle and CT in adult.

Question 6

Where does cartilage in the trachea originate?

Answer 6

Visceral mesoderm.

Question 7

What is the signalling part of the branching of the bronchi and trachea?

Answer 7

The mesoderm induces the endoderm to branch.

Question 8

What are the stages in bronchi and lung development

Answer 8

1. Pseudoglandular stage (diverticulum surrounded by cuboidal cells), 2. Canalicular period, 3. Terminal sac (24 weeks-birth, differentiation of type II cells, capillaries adjacent to epithelium-squamous), 4. Alveolar period (birth-8y)

Question 9

How does the immune system signal delivery from surfactant?

Answer 9

Macrophages in amniotic fluid phagocytose surfactant and enter tissue–>uterine muscle secretes interleukin 1-beta which releases prostaglandins, which induce muscle contraction and labor.