Lung Development Stages Quiz

During which stage of lung development do terminal bronchioles form, but without the presence of respiratory bronchioles or alveoli?

At what stage of lung development do type II pneumocytes begin to appear, and what is their primary function?

In what stage does capillary contact with developing air sacs become close, facilitating significant gas exchange?

During which stage of lung development would a premature birth be most likely to result in a relatively good survival rate, assuming available support and treatment?

Mature alveoli with epithelial-endothelial contact are characteristic of which stage of lung development?

Lung Development Stages

Stage P (5-16 Weeks):
- Lung structure limited to terminal bronchioles, no respiratory bronchioles or alveoli.
- Capillaries are near but do not have contact with the developing lung structures.
- Premature birth at this stage is not possible (0% survival).
Stage C (16-25 Weeks):
- Respiratory bronchioles begin to form.
- Only a limited number of terminal sacs present.
- Very few alveolar sacs are developed.
- Premature birth survival is significantly low (9-33%).
Stage TS (26 Weeks - Birth):
- A substantial number of terminal sacs and alveolar sacs are evident
- Pneumocytes, critical for gas exchange, are present:
  - Type 1 pneumocytes are essential for gas exchange.
  - Type 2 pneumocytes start producing surfactant towards the end of the 6th month
- Surfactant production at sufficient levels is achieved about two weeks before birth.
- Capillaries establish close contact with developing lung structures.
- Premature birth survival is relatively high (68-94%) with additional support/treatment.
Stage A (Birth - 8 Years):
- Alveoli are fully matured, reaching their mature size and shape and maximizing epithelial-endothelial contact to support the efficient gas exchange function.
- Premature birth survival rates are very good (approaching 100%) at this stage.

Test your knowledge on the stages of lung development from 5 weeks to birth. This quiz covers key features of each stage, including the structures involved and the implications for premature birth. Understand how lung maturation progresses and the critical roles of different pneumocytes.