From the onset of internal pipping (i.e. embryonal breathing of air cell gas) until hatching, the chorioallantoic membrane (CAM) and the lungs work simultaneously to serve the metabolic needs of the embryo. (1) The carbon dioxide and oxygen exchange rates (V̊O2 and V̊CO2) through the lungs and the CAM were separately, but simultaneously, measured during the last two days of incubation (day 20--21), while ventilation (V̊E) was calculated from the measurements of pressure oscillations in the air cell. When the embryo's total metabolic rate was increased, V̊E was linearly proportional to lung V̊O2 and V̊CO2 and not to the embryo's total metabolic rate. (2) Tracheal pressure and changes in lung volume were quantified through mechanical ventilation of the embryo. The curled up posture of the embryo, the eggshell and its membranes did not represent a significant mechanical constraint to V̊E. (3) V̊E, lung V̊O2 and V̊CO 2 were measured while the CAM compartment was exposed to either 10% O2, 100% O2 or 5% CO2. Total V̊O2 was also measured under these conditions. There is a clear V̊E-sensitivity to CO2 and a rather weak V̊E-sensitivity to changes in arterial oxygenation present at this stage of development.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33811 |
| Date | January 2001 |
| Creators | Menna, Tara Marisa. |
| Contributors | Mortola, Jacopo P. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001863590, proquestno: MQ78928, Theses scanned by UMI/ProQuest. |
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