Anatomy and Development

Question 1

List the path of airflow through the lungs

Answer 1

Trachea -> Main Bronchus -> Bronchioles -> Terminal Bronchioles -> Respiratory Bronchioles -> Alveolar Ducts -> Alveolar Sacs

Question 2

What are the two main functions of the lungs?

Answer 2

1) Conduction of gas from atmosphere

2) Equilibration of oxygen and carbon dioxide in capillary beds

Question 3

What two processes affect gas exchange?

Answer 3

Ventilation and perfusion

Question 4

What structures affect ventilation?

Answer 4

Lungs, chest wall muscles

Question 5

What structures affect perfusion?

Answer 5

Heart and circulatory vessels

Question 6

What conducting structures have cartilage?

Answer 6

Trachea and bronchi

Question 7

What structures have smooth muscles?

Answer 7

Large bronchi and bronchioles (none in trachea or small bronchi)

Question 8

What cell type comprises 95% of the alveolar endothelium?

Answer 8

Type I Pneumocytes

Question 9

What are the functions of Type II Pneumocytes?

Answer 9

1) Surfactant secretion

2) Repair or replacement of damaged Type I Pneumocytes

Question 10

What is the distribution of pulmonary arteries, veins, and lymphatic vessels?

Answer 10

Pulmonary arteries course the bronchi to allow interface
Pulmonary veins run along the peripheral
Lymphatics follow both arteries and veins to cope with extravascular lung water

Question 11

What are the stages of lung development?

Answer 11

Embryonic, pseudoglandular, canalicular, saccular, and alveolar stages.

Question 12

What occurs in the embryonic stage?

Answer 12

Lung bud forms from the gut tube (endoderm) into the surrounding mesenchyme, bud branches into 3 lobes.
26 days to 6 weeks gestation.
Circulation begins to develop.

Question 13

What occurs in the pseudoglandular stage?

Answer 13

Lung bud branches 14 time to form terminal bronchioles.

6 to 16 weeks gestation.

Question 14

What occurs in the canalicular stage?

Answer 14

Terminal bronchioles divide into respiratory bronchioles.
Surfactant production begins slowly.
16 to 28 weeks gestation.

Question 15

At what age is the respiratory system viable?

Answer 15

26-28 weeks gestation

Question 16

What occurs in the saccular stage?

Answer 16

Respiratory bronchioles divide into terminal sacs. These continue to form in childhood.
28-36 weeks gestation

Question 17

What occurs in the alveolar stage?

Answer 17

The lungs and alveoli grow and mature, alveolar septa thin, a single capillary network is established in the alveoli, the gas exchange units are established.
36 weeks gestation to 4-6 years of age

Question 18

Which development stages produce conducting airways?

Answer 18

Embryonic and pseudoglandular

Question 19

What development stages produce gas exchange structures?

Answer 19

Canalicular, saccular and alveolar

Question 20

What are the common pulmonary problems at birth?

Answer 20

Tracheoesophageal fistulas (connecting tube)
Tracheal or pulmonary atresia (incomplete connected tube)
Respiratory distress syndrome
Gross malformations
Congenital cysts