2017 Group Project 5: Difference between revisions
From Embryology
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4. Saccular (weeks 24-40) | 4. Saccular (weeks 24-40) | ||
5. Alveolar (week 36-8 years) | 5. Alveolar (week 36-8 years) | ||
{{lung stage table}} | |||
===The Respiratory Zone=== | ===The Respiratory Zone=== | ||
Revision as of 16:37, 31 August 2017
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Lungs
An introduction to the lungs...
On this page, we will be exploring the development of the lungs through the stages of embryonic growth.
Developmental origin overview
The Lung Development Stages
1. Embryonic (weeks 4-5) 2. Pseudoglandular (weeks 5-17) 3. Canalicular (weeks 16-25) 4. Saccular (weeks 24-40) 5. Alveolar (week 36-8 years)
| Lung Stage | Human | Features | Vascular | |
|---|---|---|---|---|
| Embryonic | week 4 to 5 | lung buds originate as an outgrowth from the ventral wall of the foregut where lobar division occurs | extra pulmonary artery then lobular artery | |
| Pseudoglandular | week 5 to 17 | conducting epithelial tubes surrounded by thick mesenchyme are formed, extensive airway branching | Pre-acinar arteries | |
| Canalicular | week 16 to 25 | bronchioles are produced, increasing number of capillaries in close contact with cuboidal epithelium and the beginning of alveolar epithelium development | Intra-acinar arteries | |
| Saccular | week 24 to 40 | alveolar ducts and air sacs are developed | alveolar duct arteries | |
| Alveolar | late fetal to 8 years | secondary septation occurs, marked increase of the number and size of capillaries and alveoli | alveolar capillaries | |
| embryonic stage - pseudoglandular stage - canalicular stage - saccular stage - alveolar stage Links: Species Stage Comparison | respiratory | ||||
The Respiratory Zone
- The terminal bronchioles - Alveolar ducts - Alveoli
